314046

JPRS-JST-87-027

23 SEPTEMBER iqS7

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FOREIGN

BROADCAST

INFORMATION

SERVICE

JPRS Report—

Science &

Technology

Japan

www m

Approved tear pa&üs r«i«*ase;

Dtotribottoa Unlimited

MIC QUALITY INSPECTED I

REPRODUCED BY

U.S. DEPARTMENT OF COMMERCE

NATIONAL TECHNICAL

INFORMATION SERVICE

SPRINGFIELD, VA. 22161
JPRS-JST-87-027

23 SEPTEMBER 1987

SCIENCE & TECHNOLOGY

JAPAN

CONTENTS

ADVANCED MATERIALS

Hitachi Develops Ceramic Superconducting Device

(KYODO, 11 Aug 87) !

Recent Trends in Superconductor Development Discussed

(Hideo Ihara; SHIN KINZOKU KOGYO, Summer 1986) 2

Material Design of High Performance Glasses Discussed

(KINO ZAIRYO, Feb 87) 17

Briefs

Superconducting Material Development 30

AEROSPACE, CIVIL AVIATION

Country Plans Three-Axis Weather Satellite

(AEROSPACE JAPAN-WEEKLY, 3 Aug 87) 3!

MOS-1 To Be Launched in January 1988

(AEROSPACE JAPAN-WEEKLY, 3 Aug 87) 32

H-ll To Be Powered by New Engine

(AEROSPACE JAPAN-WEEKLY, 3 Aug 87) 33

AUTOMOTIVE INDUSTRY

Development, Features of Roller Rocker Arm Reported

(NAINEI KIKAN, Jun 87) 34

-a-
1

DEFENSE INDUSTRIES

Japan, U.S. Agree on SDI Research

(AEROSPACE JAPAN-WEEKLY, 3 Aug 87) 37

XSSM-1 Proving Excellent Performance in U.S.

(AEROSPACE JAPAN-WEEKLY, 3 Aug 87) 38

Defense Agency Officials Divided on FSX Plan

(KYODO, 15 Aug 87) 39

FS-X Expected Not To Be Upset by Senate Resolution

(AEROSPACE JAPAN-WEEKLY, 3 Aug 87) 41

Prospects for Ceiling on Defense Budget Proposal

(AEROSPACE JAPAN-WEEKLY, 3 Aug 87) 43

ASDF To Select AFIS in August

(AEROSPACE JAPAN-WEEKLY, 3 Aug 87) 45

Briefs

Astronomers Oppose SDI 46

ENERGY

Synchrotron Radiation Development Status Reported

(Yuuta Sagara; TOSHI KEIZAI, Nov 86) 47

LASERS, SENSORS, OPTICS

Developments in Optical Sensor Technologies Described

(Tatehiko Hidaka; OPTRONICS, Dec 86)

Laser Development, Evolution of Applied Technologies Described

(Takuzo Sato; OPTRONICS, Jan 87)

TELECOMMUNICATIONS

Status, Outlook of Optical Technology in Information Equipment

Field

(OPTRONICS, Mar 87) 74

/9987

50

63

- b
ADVANCED MATERIALS

HITACHI DEVELOPS CERAMIC SUPERCONDUCTING DEVICE

OW111017 Tokyo KYODO in English 1003 GMT 11 Aug 87

[Text] Tokyo, 11 August KYODO—Hitachi Ltd. said Tuesday it has testmanufactured a ceramic superconducting quantum interference device (squid)

that it made into the form of a fine film by applying its semiconductor fine

process technology.

The new squid, which reached its superconducting temperature through cooling

with cheap liquid nitrogen at minus 196 C, can detect faint magnetic fields

with a strength only a 10 millionth that of the earth's magnetic field.

This means that the new squid can be incorporated into medical diagnostic

equipment intended for diagnosing brain and heart disorders by catching

changes in the extremely weak magnetic fields these organs generate, the

company said.

Hitachi's new squid is made using a high-frequency sputtering process to form

a thin film of yttrium-barium-copper oxide onto a substrate of magnesium

oxide, which is then heat-treated in an oxygen environment.

The resulting superconducting film is one to two microns thick (a micron

equals 1/1,000th of a millimeter) and superconducts at minus 187 C, at which

temperature it has a maximum current density in excess of 6,000 amperes per

square centimeter.

Optical exposure and chemical etching processes are then used to make a hole

in the middle of the film, after which two Josephson junctions are connected

to both of the hold to form a squid.

International Business Machines Corp. announced a thin-film ceramic squid

similar to the Hitachi squid in April. However, the IBM squid has to be

cooled to minus 205 C, and is not as sensitive as the hitachi squid.

Hitachi said it plans to officially announce its new squid at the

international superconducting electronics conference, which will be held in

Tokyo 28-29 August.

/12232

CSO: 4306/0523
ADVANCED MATERIALS

RECENT TRENDS IN SUPERCONDUCTOR DEVELOPMENT DISCUSSED

Tokyo SHIN KINZOKU KOGYO in Japanese Summer 1986 pp 1-8

[Article by Hideo Ihara, Electrotechnical Laboratory: "Recent Developments in

New High-Field Superconductors"]

[Text] 1. Introduction

Broad new fields of application for superconductors are opening up in the

forms of superconducting magnets, power storage, power transmission, etc., as

well as transformations in medical treatment and the manufacturing industry.

In the electronics fields, also, the future for new materials is bright with

regard to Josephson elements and Fluxon elements. in addition to the

conventional superconductors Nb, NbTi, NbßSn, and VßGa, such new materials as

Nb3Al, NbßGe, NbN, and PbMogSg have been added, with considerable interest

focused on their application. A new phase was also ushered in with the

availability of such new materials as the superconductors MoN and UBe^, the

compound function superconductor BaPb^.xBix03, the artificial lattice

superconductor Au/Cr, and the organic superconductor (BEDT-TTF)2l3-

Topics for superconductor development fall into the following six categories:

(1) Development of high critical temperature (Tc) materials

(2) Development of higher critical magnetic field (H^) and high critical

electric current density (Jc) materials

(3) Development of materials for high-performance Josephson elements and

Fluxon elements

(4) Development of superconductors with new functions

(6) Development of superconductors with new materials

Development objectives for these categories are summarized along with related

materials in Table 1.

The need for high-T materials mentioned in (1), in a word, lies in escape from

the restrictions imposed by liquid He. This becomes quite obvious when we

consider both the technological and economic burdens of the refrigeration
Table 1. Areas of Superconductor Development

Area of development Developmental objective Material system

(1) High-T_ materials

(2) High-Hc and high-Jc

materials

At present 30K, next

100K, finally 300K

Wire making of present

materials 100T, finally

1000T

Nb3Si, Nb3C, MoN, RuN

Nb3AlN(Al,Ge)Nb3Ge,

NbN PbMo6S8,

application of f

electrons

(3) High-performance J

element and f element

materials

High speed, high reliability, high durability

Nb, NbN, Nb3Ge, Nb3Al

(4) New-mechanism superconductors

(5) New-function superconductors

(6) New-material superconductors

Superconductors with

exciton and plasmon

mechanism, Tc approximately 1000 K

Superconductors of light

and magnetism linking

Moving toward high Tc

for organic conductors

CuCl(?) CdS(?)

Artificial lattices,

low-dimensional

materials

BaPb1.xBixBix03,

LixTi2.x03

(BEDT-TTF)2I3

required for liquid He, and also the instability of future He supplies. For

these reasons, and as can also be seen from Figure 1, development of

superconductors with Tc of 30-35 K is needed. If a closed cycle cooling

system is possible, then superconductor technology will require only a power

source for use any time, any place. This can be expected to hasten

popularization. The use of liquid hydrogen and liquid Ne is also meaningful

in consideration of reduced refrigeration cost and freedom from problems of

raw resources availability.

Developmental objective (2) is now the formation into wire of previously

available superconductors Nb3Al, Nb3(AlQ 7Ge0 3)Nb3Ge, and PbMogSß. For the

long term, there is the need for research to increase the high-Tc properties

of heavy fermion superconductors which have a good probability of showing high

T

c2-

With regard to (3), Nb and NbN will be basic materials in the near future,

with Nb3Ge and the A15 compound Nb3Al the subjects of special applications.

Because of the poor durability and reliability of Pb alloys, it seems certain

that they will be replaced by materials of the Nb family.

Objective (4) is the implementation of high-T superconductors with new

superconductor structuring by means of (plasmons) (quanta of collective

i
Temperature f°0

Absolute tenperature <IQ

Superconductor critical tewpgratnw

- 1,000 K

300 K

X

c

i

t

n

e

c

h

s

u

p

e

TiBuOWK?)-

Cholio acid

systens

100X

OX

o a r

n n

1

c

o

Nb-Si(180K?)- -100X

P

1

s

n

n

d

a u CuCKlOOK?)-

s

n t CdS(77K?)- -200X

o

n

o 1

r Nb3C(55K?)-

'40 K

P s

h u

o p

n e

o r

n o

o

PI n

e d

o u

h o

a t

n o

i r

s s

PI

Nb3Si(25~38K?iMoN(25~29K?)-

Nb,Ge(23.9K>- -250XNb3AUGeOJs(21K)-

Nb3Sn,NbN(~l8K)-

Nb(9.3K)-

-270X-

[Coolant Itenper- lature I

-373.15K ftflft boilin9

-300K

-273.15 K

-194.65 K

Melting point

or ice

Sublinination

point oF dry ice

Ü

— nu;if Boilin' point ioo K Jiv £ gr netnane

— 90.188K Boiling point

''•*>«* Boiling point

of nitrogen

1T0 of anticipated superoonduotor

—Boiling point of neon

20.28 K

Boiling point of

hydrpgen

]Tc oF actual

I superconductor

]()K T [Closed cycle

jooollng

4.25KBoiling point oF

heliun

2.15KHeliun superFluid

(Hell)

(Values For boiling

IK and sublination points

at 1 atn)

Figure 1, Critical Temperature (Tc) and

Coolant Temperature for Superconductors

excited state electrons) and (excitons) (quanta of electrons and positive

holes bonded together by static force), which will replace current

superconductor structuring by means of phonons (lattice vibration). There are

also methods which use a position shift in phase-completing electron density

waves, without creating these sorts of electron pairs.

(5) is designed to link superconductors with characteristics of light,

electricity, magnetism, heat, force, radiation, etc., to obtain new functions

from these superconductors. Examples include such photosensitive materials as

BaPbl-xBix°3 and such magnetic superconductors as ErRtv^ and HoPb6Sg.
(6) involves superconductors which use as constituents materials other than

ordinary inorganic metals, including organic materials and oxides. These

materials can be included in any of the functional categories (l)-(5), but in

terms of the growth of new materials, they should receive special

consideration as an independent category.

Directions of development for superconductor wire and material for Josephson

elements were explained previously by Tachikawa and Mikoshiba in this

publication, and will not be duplicated here. Instead, we will emphasize the

developmental directions for new superconductors beyond those. Materials

discussed here will be new high-Tc superconductors, oxide superconductors

having optical sensor functions, heavy fermion superconductors having a good

probability of giving rise to high Hc2 superconductors, and organic

superconductors having some probability of becoming new material

superconductors.

2. New High-Tc Materials

Categories of high-Tc materials vary depending on the developmental objectives

of Tc. At present, normally those materials are considered which have a Tc of

15 K or above but less than 20 as shown in Table 2. However, the objects of

future practical research will probably show higher Tcs than such materials

currently in use, including Nb3Sn wire (18.4 K) and NbN Josephson elements

(17.3 K). In the area of wire development, materials having a high Tc include

Nb3Ga (20.3 K), Nb3(Al0.7Ge0 3) (20.7 K) and Nb3Ge (23.9 K). In the

electronics field, this category includes materials of A15-type structure,

including Nb3Sn. The reader should refer to footnoted documents (2) and (3)

for more information on these materials.

From the point of view of developing new high-Tc materials, there are

previously popular materials which presently have a low Tc but demonstrate the

possibility of rasing the maximum Tc value (23.9 K). These include such

materials as Nb3Si, Nb3C and V3C, which have the A15-type structure, and MoN,

RuN, and RhN, which have the Bl-type structure. These materials having a

high-Tc are substances not present in equilibrium phase diagrams, and are

extremely difficult to synthesize. The cause of this difficulty in synthesis

turns out to be the cause of the high T. In other words, research and

development regarding high-Tc materials becomes R&D on the technology of

nonequilibrium materials synthesis itself. It seems apparent that both the

difficulties and the points of interest in future R&D on these high-Tc

materials will lie in this area.

Why, then, do the Al5-form Nb3Si and Nb3C yield high Tcs? The answer is

provided by empirical rule, from a lattice constant and Tc. When an A15-type

compound of the Nb family is graphed and plotted as shown in Figure 2, with

the lattice constant on the horizontal axis and Tc on the vertical axis, then

Tc can be predicted for Nb3Si of 30 K, and for Nb3C, with a lattice constant

of 4.08 A, of over 77 K. A separate empirical rule form Dew-Hughes predicts

values for Nb3Si and Nb3C of 38 K and 55 K, respectively. Al5-type Nb3X

compounds can be stabilized in a state of equilibrium when the atomic radius

ratio lies in the range of 0.97 < rjj/r^ < 1.065. Since rg/r^ - 0.88 and

r

c/rNb =0.51, the production of Nb3Si and, in particular that of Nb3C,
Table 2. Characteristics of High-Tc Superconductors (Tc > 15 K)

State Symmetry Structure Superconductor TC(K) HCl(T)

(4.2K)

Gap energy

,d(0)(meV)

Coherenoe

length

i(0)(nm)

Magnetic

HMEngtn1

MOjCnm)

B

C

3

0

a

t

e

v

n

n

n

49

C

II

c

0

0.

e

0

0

0

3

h

w

H

«

n

t

0

0

H

A

3

U

A15

n

ii

ii

II

II

II

II

Nb3Ge

Nb3(A]0.7Ge0.3)

Nb3Ga

Nb3Al

Nb3Sn

VjSi

VjGa

MojRe

23.9

20.7

20.3

18.9

18.5

16.9

16.8

15

37

42

34

32.5

28

25

27

3.9

3.5

3.4

2.5

~3

~3

~3

~3

130

(150)

170

(150)

0

u Bl

//

D5f

NbN

NbCo.jN«.,

I »0.7 bo.3)jC3

17.3

17.9

17.0

43

17

2.5 ~3 200

1 L12 Nb3Ruj 16.0

Tetra- gonal

crystal Hexa- gonal orystal

D8b Mo3Tc,

MoN

15.8

16.3

three

oonp.

*v«tt.i»r

Rhombus

crystal PbMo6S6 15.2 50 2.4

A

1

1

three

eonp.

syster

Cubic

crystal

i'

Bl(fcc)

//

PdCuH

PdAgH

16.6

15.6

y

s

tuo

oonp.

syster

Cubio

orystal A2(bcc) MoTc 16.0

becomes difficult. This is because on each face of the body-centered cubic

lattice formed by Si or C, two Nb atoms must be skewered like dumplings on a

stick, with negative effects for the atomic radius ratio. Thus, the very

cause of a raise in Tc also causes an increase in the difficulty of synthesis.

At present, a T of 19 K can be implemented for NbSi through application of 1 M

bar (one million atmospheres) through explosion compression. With NbßGe, up

to the present, only values of 13 K and below have been obtained using such

methods as CVD, simultaneous vapor deposition, and the sputter method

achieving 2.3 K and above. In the future, it will be necessary to develop

synthesizing processes using negative ions and plasma to increase the ion

radius of Si and C.

For such Bl-type compounds as MoN and RuN, as shown through empirical rules in

Figure 3, the relationship between the lattice constant and Tc predicts a Tc

of approximately 30 K for MoN, TcN, RuN, and RhN. Also, in addition to the

nitrides, the relationship between the electron state density N(Ep) and Tc

predicts a Tc of approximately 23-32 K for Tc, Ru, and Rh. When easily

generated lattice vibration irregularities and instability in covalent bonding

are added to substances having these high electron state densities, even
a 25

20

i7j %

(Nb3Si)\

Measured 0

value

1 Predicted

(Nb3Ge)\

\ NboGe

lNb,(Al,Ge)

HNbaGa

\NbjAl

Nb,(Ga,Sn) Nb3Sn

15 JU j_ j_

5.0 5.1 5.2 5.3 5.4

Lattioe oonstanta(A)

Figure 2. Relationship Between Lattice Constant and Tc for A15-Type Nb

Based Compounds

,o

10

—Theoritical Prediction

Kr S\\

NbC0.3N

0.7

400 425 450 - 475

(a) Lattice Constant a(Ä)

f Phonon

anomaly

Spin fluctuation

0.5 1.0

States

eV«Primitive ceIT)

Figure 3. Relationship Between Tc for Bl-Type Transition Metal Nitrides

and Carbides, and Lattice Constant (a) and Electron State Density

<

b

>

higher Tc can be expected. The above are based on empirical rules, but for

MoN we have precise Tc calculations based on band calculations, form which a T

of 29.3 K can be estimated. The authors have also confirmed the accuracy of

these band calculations, and consider these estimates to be highly accurate.
Synthesis of Bl-MoN has been attempted in the United States, Japan, and

Germany, with theoretical estimates by the NR1 group in the United States of

9 K, by the authors of 13 K, and by Linker and associates in Germany of 6 K.

Actually, more than 10 other groups have also attempted synthesis using the

sputter and high pressure methods, but their results have been far from the

target Tc.

The causes of low Tc lie in the presence of large quantities of unbonded N and

of N space lattices within the Bl-MoN crystals. This incomplete Mo and N

bonding is caused by the fact that a large part of the electron structure of

Bl-MoN is in antibonding status, making bonds unstable. In order to raise the

Tc for the Bl-type transition metal compounds it is necessary to increase the

electron state density and thus increase the number of valence electrons.

Then the proportion of antibonding orbits will increase and bonds will become

destabilized. Even here, the principle, which causes Tc elevation, makes

production difficult. Such methods as the use of active electron state

nitrogen and atomic ions, catalytic effects, the optical atomic level

epitaxial method and high-pressure high-temperature processing are thought to

be effective in overcoming this problem, and are being widely tested.

We will discuss one method of high-pressure synthesis. This method was chosen

for testing because, although there is hex-Mon in the Bl-MoN combined phase,

the packed density of electrons in the Bl phase is higher, so that there is

more possibility of improved crystallization and hex--Bl phase transition with

high-pressure high-temperature treatment. When Bl-MoN crystals were processed

under 6 GPa of pressure at a temperature range of 700-l,400°C, phase

transition was observed from the Bl phase to the hex phase for all but a small

portion of the sample. The maximum Tc was 16.3 K which, as Table 1 shows, is

the highest Tc obtained for presently available superconductors consisting of

other than cubic crystal materials. This is of great importance, since actual

experience to date has normally shown higher Tc values for cubic crystals than

for hexagonal ones. As Figure 4 shows, it is known that when crystals of the

same composition are changed from hexagonal to cubic there is an increase in

Tc of 5-10 K. From this, too, we can estimate a Tc of 21-26 K for Bl-MoN if

perfect crystals could be obtained. In addition, a Tc for perfect Bl-MoN

crystals of approximately 25 K can be estimated from the N space lattice

concentration for Bl-MoN and the electron state density ratio for hex MoN and

Bl-MoN. It is only a question of time until the Tc for Bl-MoN exceeds the Tc

for NbN and reaches 20 K or above.

A Tc of 30 K is also estimated for Bl-RuN, and at present production is being

attempted. Production of this substance is difficult, since the antibonding

orbit specific gravity is greater than that for MoN. At present, Bl-RuN

crystals have not been successfully obtained in perfect form, but a Tc of 10 K

or above has been obtained for systems having a low nitrogen content. This Tc

is still low, but since relatively high Tc values have been obtained so

simply, it appears that Ru-N systems will provide superconductors having high

Tc properties. Although there is some hope for the future, implementation

will be difficult since at present Ru is among the precious metals, with only

approximately 8 tons produced annually worldwide. Reserves should be

confirmed. There are also expectations for TcN and RhN, but these face

similar difficulties with regard to resources.
Figure 4. Relation Between Crystal Structure and Tc for Transition Metal

Compounds

Other high-Tc materials research has taken the form of investigating new

crystal forms other than A15-type and Bl-type compounds. This research does

not involve the expansion of already existing materials, so the linear

estimates used up to this point do not hold. Instead, a qualitative leap in

materials design methods is required. Presenting results only for the sake of

documentary convenience, such cubic crystals as Y-Mo-B, Y-Nb-B, Y-Nb-P and YMo-P are powerful candidates. Y and Mo, and Y and Nb, show nonsolidsolubility, and do not react, while through B or P both can be bonded. Such

action by B or P is termed the "Gorota Ishi" [small-stone] effect. These

physical systems are also in a disequilibrium phase. It seems likely that the

new physical systems resulting from such combinations with nonsolid-soluble

elements will provide a direction for future investigations into high-Tc

materials.

3. Oxide Superconductor Materials

Attention has been focused on oxide superconductors in particular because they

are expected to provide superconductor materials with a surprisingly high Tc

for oxides and with a high degree of optical permeability and good optical

performance due to the low carrier concentration. Oxides with Tcs of 4.2 K or

above include Li1+X Ti2.x04 (13.7 K), BaPbP.xBix03) (13 K), RbxWO (7.3 KO and

CsxW03 (6.2 K). The characteristics of the first three are shown in Table 3.

Of particular interest is BaPb;L_xBix03. This material shows a high Tc even

though its carrier concentration is one order of magnitude lower than that for

ordinary superconductors. Because of the low carrier concentration, it

resembles the semiconductors in optical permeability and structural
Table 3. Characteristics of Typical Oxide Superconductors

^^--•^^^ Oxide BaPb,-„

Bi,03

^U+xTh-xOi RbxW03

Charaoter istiofev^^

Crystal form Tetra- Cubic Hexagonal

gonal crystal - crystal -

crystal spinel perouskite

TC(K) 13 13.7 7.2

HCj(T) 5.5 18.5

Electron specific heat coefficient

(mJ/mol-K2)

1.6 20 ~1

Carrier concentration

(I021cm-5)

2-3 13.5 (~2.0)

Electron state./-, \

density NVE>FJ 0.03 0.97 / states \

\ eV • spin • atom/

Resistance _. N

rate p\fAl cm) 545 20000 (1000)

Effectivemassim(m*/m\ /m) 0.5 9.4 Reflectiue,.. .

ratelf(%) 3

^ X=lurn Absorption .

coefficient(cm ') 105

A=l j/m

sensitivity. This material is also of interest because it shows the highest

Tc of the materials with superconductor electrons made up only of sp

electrons, and because of its particularly high degree of electron/lattice

interaction.

BaPb^.xBx03 is a solid solution of BaPbOß and BaBiOß, taking on a Perovskite

structure. The superconductor consists of tetragonal crystals in a range of

0.05 < 0.3, with Tc maximized when x is approximately 0.25. The material

shows good optical permeability due to its low carrier concentration; at a

thickness of 300 nm, the backing is visible. The substance shows considerable

mutual interaction with infrared rays, having actual optical characteristics

of 0.6 ym of 10 percent reflectivity and absorbance coefficient 10^ cm"1at

wavelengths of 0.6 ym, and 3 percent reflectivity and absorbance coefficient

of 105cm"1at wavelengths of 1 ym.

The optical detection mechanism of superconductors uses transition across an

energy gap, and in this point superficially resembles the use of band gap

transition by semiconductor sensors. However, the content is quite different.

In principle, a light beam activates the superconductor electron pairs, while

decreases the energy gap, and shows a nonequalibrium superconductor effect.

This makes it possible to utilize changes in the characteristic Josephson

junction I-V gap voltage corresponding with the amount of illumination. This

point differs from the photoelectric effect found in semiconductors, in which

the current varies with the amount of illumination.

10
When using BaPb^.xBix03 in a sensor, one method involves using the particle

boundaries which occur in sputter membranes as Josephson junction barriers.

For sputter membranes of approximately 200 nm in thickness, aggregates of

crystals having approximate diameters of 250 nm are formed. When these are

heat-treated in an oxidizing atmosphere at 600°C, lead oxides are volatilized

from the highly flawed particle boundaries, and the particle boundaries are

converted to insulators. In this way, using the particle boundaries as a

barrier, the crystals form Josephson junctions. If 10-unit particle

boundaries are separated and a voltage bias is applied, then 10 elements are

linked in series, a voltage of 10 times the initial magnitude is generated,

and sensitivity is increased by that amount.

The importance for optical sensor materials of low carrier concentration in

oxide superconductors lies in the fact that illumination-caused changes in the

energy gap 6A are inversely proportional to the electron state density N(EF),

in other words the carrier concentration. For this reason, BaPb^.xBix03 snows

a sensitivity 10 times greater than that of ordinary superconductors. In the

case of Lii+xTi2-x04, the d electrons participate, so that the carrier

concentration increases, making this substance unsuitable for photosensor

material. Future development is needed of materials having higher Tc and

lower carrier concentration.

4. Heavy Fermion Superconductors

Normally, the coefficient y

for electron specific heat (C - YT) is

approximately 1 mJ/mole.K . However, there are compounds of the lanthanum

(4f) and actinium (5f) series, including such superconductors as UBe^3, UPtß,

and CeCu2Si2 in which the F electrons are valence electrons, which show such

abnormally large values for y as 1,000 mJ/mole.K2or above. Because Y is

proportional to the effective electron mass (y-m*), these are called heavy

electron system or heavy Fermion system superconductors. Because the

corresponding upper critical magnetic field HC2 increases in proportion to the

increase in this Y. as Table 4 shows, HC2 is exceedingly large despite the low

T. If the Tc could be increased, there is a possibility of obtaining a

significantly higher HC2-

Table 4. Characteristics of Heavy Fermion Superconductors

~* ^^^ Conpound

Character istioiS-»^^

UBe13 UPt, CeCu2Si2

Crystal forn

Distance betuqen

•F*itens (A)

Cub io

5.13

Hexagonal

4.1

Tetragonal

4.1

y(j/moleK') 1.1 0.45 M

m*/me 192

TC(K) 0.85 0.5 0.67

HCl(0K)(T)

SPeneait(T<Tc)

>6.0

V

-2.3 ~2.0

11
An unusually large effective mass is thought to be due to the relationship

between y values and the distance between f electrons, as shown in Figure 5,

and also to the resulting narrowing of the f band, which occurs as the mutual

interaction among f electrons decreases along with reductions in the abovementioned distance. The spin fluctuation effect and the many-body effect are

also considered of major importance. In addition, there is the possibility of

superconductors having p waves from the parallel spins of superconductor

electron pairs. (In normal superconductors, the spins of electron pairs are

antiparallel, with spin sum of zero, and are termed s waves.) Experimental

evidence has been reported regarding these p-wave superconducting structures,

including specific heat and ultrasonic wave absorption. Spins are parallel

for p-wave superconductors, so a shielding effect can be anticipated for the

external magnetic field, with the possibility of producing a high-HC2

superconductor. The mechanism of this heavy Fermion superconductor is not yet

clear, but further study of the application of these materials as new

materials can be expected both because of the possibility of high-HC2

materials occurring in general and also because of the possibility of high-Tc

materials occurring if the electron state density can be increased using the f

electrons.

. i | i ii i i i i i i | I I I i i I I I 11 in I iiiiqnuinnm

CeC^Siip**V^-

- Nplr,

- NpOs2l/

UAlJ* 0 /CeAlj 4i 5(

/ l/u PIC ° • superconducting

U\r2U j a magnetic

II & A not superconducting

^6 *o/CeOs2 or magnetic

a-Np7 / AYbAI2

o-U 1 /Oo-ce

i I i t i i i i t l i I i i i i i i i i i I I 111 ill

3 4 5 6 7

( atom spacing (A)

Figure 5. Interrelationship Between Electron Specific Heat Coefficient and

Distance f Atoms for f Electron Materials

5. Organic Superconductors

The motivation for development of organic superconductors was the formation of

one-dimensional organic superconductors of exciton structure with high Tcs as

proposed by Little. This structure makes it possible to form electron pairs

among the conducting electrons in the main chains by means of side chain

electronic polarization (exciton), yielding a high Tc (approximately 1000 K).

However, the first organic conductor substance, (TMTSF^PFg (shown in Figure

6), was not in the direction of the exciton structure organic superconductor

proposed by Little, but instead was discovered as an extension of highly

conductive ordinary charge transfer complex single-dimension organic metals.

One-dimensional organic conductors, including TTF TCNQ and TMTSF TCNQ, which

were organic metals with electric conductivity of 10-10^ (ST^-cm"1), were

12
I

7

C

Se ,CHa

N

' \ / c

a\/ Se

,c - c '

\ /Cs

Se CHa

f

TMTSF

\

PFe

7%

direction

of high

conductivity

Figure 6. (TMTSF)2 Molecules and Their Crystal Structures

discovered earlier. However, the lattice instability characteristic of onedimensional metals was generated at low temperatures, with metal-insulator

transitions (termed Peierls transitions by the author of proposal) such as CDW

(charge density wave) transition occurring and resulting in demetalizing of

the material. A superconductor phase could be expected if the onedimensionality were encouraged through horizontal mutual interaction, the

metal-insulator transition temperature (T^j) lowered as far as possible, and

the metal phase continued down to extremely low temperatures. A number of

tests have been performed concerning donor-acceptor recombination for charge

transfer complexes, high-pressure experiments, and chemical modification

methods.

In the midst of all this, in 1980 such materials as (TMTSF) 2PF6 and

(TMTSF)2AsFg synthesized by Bechgaard and associates were discovered to have a

TMI of 20 K or less. Jorome and Bechgaard then used the TJJI reduction effect

based on the strengthening of mutual interactions in the horizontal direction

through compression confirmed by a TMTSF-DMTCNQ system (TMTSF molecules are

flat, as shown in Figure 4; the stack forms a one-dimensional column). This

was used to show that superconductor transitions occurred in (TMSTSF^PFg.

Undeniably, there are points in this announcement which were developed from

Little's organic superconductor proposal for exciton structure. However, it

does not follow that earlier proposal since both the structure and mechanism

are completely different. Certainly the framework of discoveries in this

field is based on the earlier pursuit of organic materials having high

conductivity, which led to the production of organic metals, and the ability

to maintain this metal phase even at low temperatures gave rise to the

discovery of superconductive properties. Of course, with (TMTSF)Fg it is

necessary to use compression to suppress the transition to the SDW (spin

density wave) phase, which is the insulating phase, but that is not the

13
Table 5. TC(K) for Organic Superconductors: Pressure (Kbar) in Parentheses

Cation

fin ion Cx)

(TMTSF)2X (BEDT-TTF)2X

PF« 1.4 (6.5)

AsF6 1.4 (9.5)

SbF6 0.38 (10.5)

TaF6 1.35 (11 )

C104 1.4

RcO» 1.2 (9.5) ~2 (74)

FSOj 3 (5 )

I3

2.5

8 (1.3)

A11I3 5.0

IBr2 4.2

essential point. In actuality, substances showing superconductivity have been

found in the subsequent seven categories in the (TMTSF^X series as shown in

Table 5, and (TMTSF^CTO^, with the molecular volume of X reduced and mutual

interaction (within the column) increased, shows superconductivity at normal

pressure.

Based on this idea, four categories of another organic superconductor series,

the (BEDT-TTF)2X series as shown in Table 5, have been created using the

suppression of the Peierls transition through dimensionality increased by the

chemical modification method. In particular, (BEDT-TTF^I shows a Tc of 1.3 K

for formed crystals, but after compression processing at 1.3 K bar, a T of 8 K

was discovered even when the pressure was released. Aul2 shows point symmetry

and has a molecular length shorter than that of I3; because of the increase in

mutual interaction between the columns (BEDT-TTF)2Aul2 shows a measured Tc of

5 K even at normal pressure.

Organic compound superconductors and inorganic compound superconductors differ

on a number of points, the former characterized as follows.

(1) They are composed of such commonly available elements as C, H, 0, Se, I,

and Cl, thus easing problems with resources.

(2) They can be made the object of molecular design for easy improvement of

characteristics.

(3) They are configured as molecules, so there is room to build in functions

in addition to superconductivity.

(4) Because they are organic, processing and forming properties are good.

Some of these points are not particularly appropriate at this time, but the

essence is that materials possessing these characteristics are possible. If

14
materials with high Tcs become available, they will be strong rivals to

today's inorganic superconductors. The annual change in the organic

superconductor's Tc is now similar to that of the inorganic superconductors

before 1970. Whether this Tc continues to rise in accordance with the present

trend, or whether it follows the path of the inorganic systems, depends on the

capabilities of researchers in material design.

6. Conclusion

In this review we have discussed the possibilities for new superconductors.

For information on magnetic superconductors and multimembrane superconductors,

readers should refer to references (4) and (27) in the bibliography.

BIBLIOGRAPHY

1. Ihara, H., DENKI KAGAKU [J. ELECTROCHEM. SOC. JPN.], 51, 532 (1983).

2. Tachikawa, K., SHINKINZOKU KOGYO [NEW METALS INDUSTRY], 29, 29 (1982).

3. Mikoshiba, N., Ibid., 27, 99 (1982).

4. Ihara, H. and Tokano, K., "Chodendo Zairyo" [Superconductors], (Tokyo

University Press, 1986).

5. Dew-Hughes, D. and Rivin, V.G., NATURE, 250, 723 (1974).

6. Ihara, H., et al., ADVANCES IN CRYOGENICS ENGINEERING, 32, 603 (1985).

7. Pickett, W.E., et al., PHYSICS, 107B, 667 (1981).

8. Ihara, H., et al., PHYS. REV. B., 31, 3177 (1985).

9. Fuller, W.W., et al., J. VAC. SCI. TECHNOL., Al, 517 (1983).

10. Linker, G., et al., J. PHYS. F., 14, L115 (1984).

11. Toyoda, N., BOUNDARY, September 1985, p 2 (1985) (including literature).

12. Ihara, H., et al., PHYS. REV., B32 (1985).

13. Ibid., KINO ZAIRYO [FUNCTION AND MATERIALS], June 1985, p 33 (1985).

14. Terada, N., et al., (to be published).

15. Kitazawa, K., et al., KOTAI BUTSURI [SOLID PHYSICS], 18, 544 (1983).

Uchida, S., et al., Ibid., 20, 955 (1985).

16. Enomoto, Y., et al., JPN. J. APPL. PHYS., 23, L333 (1984).

17. Suzuki, M., SENSA GIJUTSU [SENSOR TECHNOLOGY], 6, No 5, 55 (1986).

15
18. Suzuki, M.. etal., J. APPL. PHYS., 56, 2083 (1984).

19. Johnson, D.C., J. LOW TEMP. PHYS., 25, 145 (1976).

20. Fukuyama, H., OY0 BUTSURI [APPLIED PHYSICS], 54, 785 (1985).

21. Meisner, G.P., et al., Ibid., 53, 1829 (1984).

22. Jerome, D., et al., J. PHYS. LETT., 41, 195 (1980).

23. Bechgaard, K., et al., PHYS. REV. LETT., 46, 852 (1981).

24. Saito, G., KOTAI BUTSURI, 19, 797 (1984).

25. Murata, K., et al., J. PHYS. SOC. JAPAN, 54, 1236 (1985).

26. Carlson, K.D., et al., SOLID STATE COMM., 57, 89 (1986).

27. Otani, A. and Tachigi, M., NIHON BUTSURI GAKKAISHI [J. PHYS. SOC. JPN.],

36, 599 (1981).

20136/9365

CSO: 4306/3669

16
ADVANCED MATERIALS

MATERIAL DESIGN OF HIGH PERFORMANCE GLASSES DISCUSSED

Tokyo KINO ZAIRYO in Japanese Feb 87 pp 42-52

[Text] 1. Introduction

High-grade materials are necessary for building a highly advanced system.

This is the reason new and up-to-date materials attract attention. In the

field of glass, a material called the new glass is attracting attention as an

up-to-date material. In view of this situation, I wish to make a survey of

the functions the new glass has as a glass and relate in what manner such a

functional glass can be designed.

2. Definition of New Glass

In the first place, new glass can be defined as a highly technical and highperformance glass. However, let us think a little more concretely on its

definition. Glass is a material used by mankind for more than 5,000 years. A

material with such a long history ought to have some valuable characteristics

worthy of its history. The characteristics of glass follow:

1) Possesses transparency and optical characteristics.

2) The continuous change of composition is possible. Therefore, the fine

adjustment of physical properties is possible.

3) Practically all elements can be taken into the glass as a solid solvent.

4) Shapes from fibrous to flat plate can be freely processed. Highly-precise

processing is also possible.

5) Possesses comparatively high strength and hardness, and it is chemically

stable.

6) Secondary processing such as crystallization, phase splitting, and ion

exchange are possible.

7) Various physical properties such as chemical and biological

characteristics, electrical characteristics, and thermal characteristics can

be provided.

17
Table 1. New Glass Classified by Characteristics

Type of glass

Characteristics

2 3 4 5 6

Refractive index distribution glass

Quartz system optical fiber

Laser glass

Photochromic glass

Delay line glass

Substrate glass

Faraday rotation glass

Porous glass

Biological glass

Chemical tempered glass

Machinable crystallized glass

Chemical cutting photosensitive glass

Radioactive waste treatment glass

Low expansion crystallized glass

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0

0 0

0 0

0

0 0 0 0

0 0 0

0 0 0

0 0

0

0

0

0

0

0

0

Characteristics:

1 Transparency, optical characteristics

2 Continuous change of position possible; continuous change of physical

properties

3 Characteristics as a solid solvent

4 Shape freedom and workability height

5 Comparatively high hardness and strength

6 Secondary processing of crystallization, phase-split and ion exchange

possible

7 Possesses various physical properties such as chemical and biological

characteristics, electrical and thermal characteristics

Table 1 shows which of these characteristics are present in glass presently

manufactured using the new glass. By using optical fiber, which plays the

leading role in optical communication, as the example, let us study what

functions have been used. First of all, transparency is a proper function for

the optical fiber. In addition to being simply transparent, there is an

engineering value in that the loss value of 0.2 dB/km which is the theoretical

value of the SiC>2 glass has been realized. By utilizing the freedom of

changing the composition mentioned in item two, an optical waveguide has been

formed by forming a core with a slightly high refractive index and a slightly

low class in a concentric circle. Fibers extending several tens of

kilometers can be prepared because of the workability mentioned in item four.

The strength and hardness mentioned in item five are extremely important for

use in utility materials.

When considered in such a way, the following definition of new glass is easier

to understand. New glass is a material that has made the best and fullest use

of the many characteristics of glass.

18
3. Itemized Discussion on New Glass

An outline will be given here on glass that is presently considered "new

glass," and on what sort of new glasses, made of up-to-date materials, will be

used in various devices in the future.

3.1. New Glass Utilizing the Optical Characteristics

(1) Refractive index distribution glass

In parallel with the progress of information transmission technology by

optical fiber and optical electronics, optical circuit parts to perform

optical branching, optical coupling, and waveform matching have become

necessary. The refractive index distribution glass realizes such functions.

There are various forms of this new glass such as the rod lens type, the flat

plate type, and optical waveguide lens.

1) Rod lens

The rod lens is rod-shaped with a high refractive index in the central part,

and a reduced refractive index in a parabolic condition towards the periphery.

Its diameter is about 1 mm. It is used as a microlens in an optical disk

pickup for converging the laser beam on the disk and for receiving light and

condensing on the diode. Moreover, the arrangement of many rod lenses

providing an equal magnification erecting image is called the lens array and

it has contributed to the compacting, weight reduction, and cost reduction of

facsimile machines and copying machines. How this lens is used is shown in

Figure 1 and example (3) in Figure 1 shows the coupling system of the optical

circuit.

LD

LED Optical Fiber

Optical

Fiber

Optical

fiber

^o^= —

Optica

Fiber

Ssniraflcction

/ filn

^\V) \ Optical

..;£>•<:- /fiber

(1) Light source

coupling'systen

(2) Parallel bean

conversion systen

(3) Position conversion systen

Object

plane

Inage

plane

P^ X2-

-«-a-v

(a)

w-a-H

FRP Plate

"Tnage"

plane

Refractive index

distribution type

lens

(b)

(4) Erecting equal

nagnification inaging systen

Adhesive

(black color)

Structure of

lens layout

(5) Inaging systen

Figure 1. Application Examples of Refractive Index Distribution Lenses

19
In general, this lens is prepared by the ion-exchange method. In other words,

a glass rod containing an ion with a high polarizability and capable of

causing an easy ion exchange (a univalent cation generally and to be concrete,

Tl+, Cs+) is prepared, this is treated in a molten salt of NaNOß, KNO3, and

ion exchange occurs. As a result, a concentration gradient could be prepared

so that ions such as Na, etc., are present close to the surface and ions such

as Tl, etc., are present in abundance close to the center. The refractive

index would be a similar shape.

2) Flat plate microlens

This lens is prepared by arranging many lenses in an array in a flat plate.

Compared with the rod lens, it is better suited for mass production because it

is flat and dielectric multilayers, filters, and diaphragms can be provided by

surface treatment. It has characteristics such as being capable of composing

an optical circuit by lamination, etc.

The flat plate microlens is prepared by the ion exchange method as is the rod

lens, however, a method for impressing the electric field and expediting the

intrusion speed of the ion has been adopted. In other words, after attaching

a thin titanium film with the thickness of ly to 2y on one side of a substrate

glass by the sputter method, patterning is made on the part introducing the

ion by the photolithography method and a circled window is prepared. This is

maintained in molten salt, an ion raising its refractive index according to

the electric field is introduced and the functions of a lens are provided.

Besides the above method, there is also the method of stacking, thin films

with a high refractive index in order on a glass substrate that has a

hemispheric hole by using the plasma CVD.

3) Optical waveguide lens

The optical waveguide prepares the functions of optical distribution, optical

coupling, etc., on a flat substrate. Types of optical waveguides are shown in

Figure 2.

Core n.

Clad n;

(a) Buildup typ»

(b) Enbedded type

(c) Microstrip type

(d) Ridge type

(e) DiFFusion

type

Figure 2. Types of Thin Film Three-Dimensional Optical Waveguides

20
(2) Energy of light transmission

Quartz glass, high-purity multicomponent glass, halogenide glass, chalcogenide

glass, and heavy-metal oxide glass can be selected according to the

transmitted optical wavelength for materials that are used for transmission

such as those that are used for communication and transmit light over a long

distance, and those that are used for a laser knife and laser material

processing machines and transmit a high-energy laser beam.

1) Quartz system glass

This glass system has already been put to use in optical communication. The

low transmission loss of 0.2 dB/km has been realized for light with a

wavelength of 1.5 ym. This is also the theoretical value. Therefore, the

future theme may be to offer a further low-priced fiber without any loss in

capacity. For achieving this purpose, the problem of what process should be

used for minimizing the OH group, which causes the transmission loss, may

become an important technical theme.

2) High-purity multicomponent system glass

Because a refractive index difference between the core and clad can be larger

in this glass than in the quartz system glass, a fiber with a high numerical

aperture can be prepared and it excels in optical coupling with the light

source. However, the transmission loss is several dB/km to 30 dB/km and it is

used for the data link between equipment at a distance of 1- to 2-km.

Although there is a possibility it may compete with plastic fiber in the

future, the high-purity multicomponent glass presently possesses

characteristics excelling the plastic fiber in the degree of more than one

digit.

3) Infrared transmission glass

When trying to obtain a fiber with a lower transmission loss than the quartz

system fiber, it is necessary to use the wavelength range decreasing the

transmission loss by Rayleigh scattering. In other words, the method of using

infrared radiation rays is the only solution. Because the transmittable

wavelength range is up to 2 ym in the quartz system fiber, a material capable

of transmitting longer wavelength infrared radiation rays should be selected.

Three types of glass are candidates for an infrared light transmitting fiber:

heavy metal oxide glass, fluoride glass, and chalcogenide glass. A minimum

transmission loss of a value one to three digits lower than the quartz system

glass can be expected. However, the actual transmission loss of the fiber

still falls short of that for the quartz system glass. (Note; The same

performance has been obtained for extremely short ones.) The reason is that

the concentration of impurities is still high; microcrystals are generated in

the glass and cause scattering. In other words, the basic problem is that it

lacks stability compared with the quartz system glass and a breakthrough is

required for future development.

21
(3) Laser glass

Because glass excels in workability and can be made into all sizes from large

to fibrous types, the application field will widen when a high=efficiency

glass laser is developed. Glass containing rare earth ions such as Nd, Yb,

Ho, Er, and Tm as active ions has been confirmed showing a laser oscillation.

However, the active ions maintained in the glass reflect the disordered

structure of the glass, the width of the oscillation spectacle is wide and the

oscillation efficiency is low. Besides the oxide system glasses such as the

silicate glass and phosphate glass, the fluoride and chalcogenide glass are

being studied as hosts. The phosphate glass, compared with other oxide system

glasses, has the characteristic of the sectional area of induction emission

being high, and in the fluoride phosphate glass the nonlinear refractive index

coefficient is small.

The laser nuclear fusion has been studied as an application of the glass laser

and has become an important theme of the gigantic chemistry.

(4) Photochromic glass

The phenomenon of changing the light transmittance by optical irradiation is

called photochromism. A glass showing such a phenomenon has been prepared and

put to use. There is the type in which the structural defects in the matrix

of the glass are centered around coloring and the type that contains silver

halide as the photosensitive crystal. An explanation of the latter type will

be given as it has already been put to use.

Glass matrices of various compositions can be used. When glass containing

silver and halogen is melted, silver and halogen are melted in ion condition

in the glass. When the glass is heat treated at an intermediate temperature

between the transition point and softening point of the glass, microcrystals

of silver halide are deposited. The transparency of the glass can be

maintained when the size of the crystal lattice is around 10 nm and the

distance between the crystal lattices is 60- to 100-nm. When ultraviolet

radiation rays or visible light rays are irradiated on crystal lattices, the

silver halide undergoes a light oxidation-reduction reaction, decomposes, and

becomes colored as an atomic silver is generated. Because coloring and

decoloring necessitate a mechanism for stabilization by means of the

structural recombination at the atomic level, those that stipulate the

coloring and decoloring speeds are those that take part in the transport

phenomenon such as the alkali ion in the glass and those that take part in the

oxidation-=reduction reaction such as copper.

The photochromic glass is presently sued in spectacles. Other applications

such as functional materials for optical memory of information storage,

switching elements, and display devices can be expected. For this purpose, it

is necessary that characteristics such as the coloring and decoloring speeds,

etc., be improved.

22
(5) Optical integrated circuit

The optical integrated circuit prepares a part with a high-refractive index

(optical waveguide) on a single substrate and integrates optical devices such

as the luminescent and light-receiving elements, optical modulator, optical

switch, optical separator, and optical filter on this substrate and is capable

of performing functions by light that had been performed up to now by

semiconductors.

The concept on the optical integrated circuit is one that has been advocated

since the latter part of the 1960s and research has been active on this

concept because expectations were held for compacting, high upgrading, and

stabilization. With the optical fiber put to practical use and importance

increasing on the optical transmission technology, research has been promoted

as a replacement for the conventional integrated circuits.

The optical integrated circuit basically consists of three elements: a light

source, various functional devices (waveguide, etc.), and a photodetecting

element. They can be classified into either the hybrid type or monolithic

type according to their form of integration.

The roles performed by glass in composing an optical integrated circuit

include forming an optical waveguide, forming the part connecting with the

fiber, and forming the passive parts of micro-optics (refractive index

distribution lens, etc.). When the monolithic integrated circuit becomes the

mainstream, GaAs, etc., may also become the mainstream.

(6) Optical memory

The optical and photomagnetic disks are being developed as devices capable of

accumulating a large volume of information. The chalcogenide glass has been

used as the memory film for the optical disk.

There are two types of optical disks, the postscript type and the rewritable

type. The postscript disk irradiates by laser on the chalcogenide glass film,

forms a hole by melting and evaporating the glass by the irradiated energy and

performs recording by this hole. The rewritable disk crystallizes the thin

noncrystalline layer by the laser ray and records using the change of he

refractive index. Heating is made by a laser with a wavelength and strength

different form the laser ray used in writing, and the record is erased by

noncrystallizing it.

Films of Te, Te-Se, Te-Ge, Te-C, Te-Se-As, Te-Se-Pb, Sb-Se, and Te-Se-Sn have

been used for recording films with excellent results.

3.2 New Glass Using the Electromagnetic Characteristics

(1) Electrochromic glass

The amorphous WO3 has been studied as the functional film for display or for

the dimmer glass. When an ultraviolet ion such as H

+

or Li+is injected into

WO3, W is reduced, it becomes of pentavalence and is colored into blue.

23
Differing from the liquid crystal display, it remains colored by the memory

effect once it has been colored. Therefore, its application as window glass,

etc. is possible. The structure of a dimmer glass is shown in Figure 3.

Electrolyte

Sealing

nateria]

EC Piln

(a-WOs)

Counter Piln

rans—

parent

electrode

Figure 3. Example of Dimmer Glass Structure

The vacuum vapor deposition method, RF sputter method, anode oxidation method,

spraying method, thermal decomposition method of organic tungsten, etc., are

used for forming the amorphous WO3 film, however, the electron beam vacuum

vapor deposition method is generally used.

These glasses are still in the development stage and there are many problems

that must be solved. Particularly, the development on the production

technology of a large area cell will become important when these glasses are

used for automobile and house windows. Moreover, since the amorphous WO3 has

the photochromic characteristic of coloring by light, the basic research on

how it should be held down will become important.

(2) Faraday rotation glass

The Faraday effect is a phenomenon in which the polarizing direction of the

linearly polarized light progressing in a solid rotates by the magnetic field.

In other words, the following equation is obtained when the angle of rotation

is made 0, the material length is made 1, and the magnetic field strength is

made H:

e - v • 1 • H

V in the above equation is the Verdet's constant and is a physical constant

peculiar to the material. In the Faraday rotation glass, a big V and a small

absorption coefficient are demanded. There are many types of glass containing

earth elements (Ce, Pr, Tb, Dy, etc.) with a large Verdet's constant.

The Faraday rotation glass has been applied to ammeters and optical isolators

in the laser optical system, i.e, elements passing light in only one

direction. Utilization as an optical switch in the optical communication and

optical measurement fields are considered future markets. The device is

capable of turning on and off the light by the electric current and the

concept drawing is shown in Figure 4.

24
Faraday

rotation .n|||—*^"N Polarizing

elenent ). ' I *{ plate

Polarizing

plate

Optical

input

Figure 4. Concept Drawing of Optical Switch

(3) Glass substrate

There are presently five glass substrates for electronic devices. They are1. Glass substrate for amorphous solar cell; 2. Glass substrate for flat

display; 3. Glass substrate for the optical, photomagnetic, and magnetic

disks; 4. Glass substrate for the photomask; and 5. Glass substrate for the

hybrid IC. The qualities needed for each application differ considerably

The substrate for the magnetic disk will probably become competitive with

existing substrates such as aluminum, etc. Moreover, because transparency is

demanded in an optical disk, optical disks may become competitive with

plastics.

3.3 New Glass Using the Mechanical, Chemical, and Thermal Characteristics

(a) Ceramic reinforced glass

Ceramic reinforced glass lacks toughness. This is a defect when it is used in

mechanical applications. Research is being done on tempered glass compounded

with ceramic fiber, etc., to correct this defect. A high modulus of

elasticity and high strength are preferable for reinforcing fibers

Therefore, carbon fiber, alumina fiber, SiC fiber, or whiskers, are used as

the reinforcing fiber. Conditions such as not reacting greatly with the fiber

and the suitable coefficient of thermal expansion are necessary for glass to

become the matrix, therefore, crystallized glasses of the Lio0-Al90,-Si09

system borosilicate system, and high-silicate glass are used. Compound

materials capable of being machined are available by selecting the reinforcing

fiber and matrix. &

This material is still in the research stage and has not been put to practical

use. Since it is lightweight and excels in high strength, high toughness, and

he!t

^

re

f

1

f

t

1

ance' development for uses in high-temperature precision machines,

artificial bones, etc., are now underway.

(2) Oxy-nitride glass

This glass has substituted a portion of the oxygen ions in an oxide glass with

nitrogen ions and as three coordination anions exist in the glass structure a

glass with high strength and excelling in heat resistance can be manufactured

ine following are the production methods:

25
(1) Method of blowing ammonia gas into melted glass.

(2) Method of treating porous glass in ammonia gas.

(3) Method of using nitrogen compound materials (SißN^m A1N), etc.

Uses for reinforcing glass fibers, etc., can be considered, however, there are

many research problems such as the difficulty of making the glass into a

fiber, etc.

(3) Chemical reinforced glass

This glass is strengthened by generating a compressive stress on the surface

layer. This is done by treating the glass in molten salt containing alkali

metal elements and replacing the alkali ions with larger alkali ions that

originally were in the glass. A glass with a higher strength than the windcooled tempered glass, which is an ordinary tempered glass, is available by

this treatment method. The strength of a chemical reinforced glass depends

upon the glass composition and treatment temperature. Glasses well suited for

chemical reinforcement are those in which the mutual diffusion coefficient of

alkali ions is great and those with a small amount of noncross-linking oxygen.

Therefore, a glass with AI2O3, TiC>2, and ZrC>2 added to the silicate system

glass has been selected.

The chemical reinforced glass has been used for spectacle lenses, watch

covers, etc. In the future, new uses such as for optical memory-related

substrate glass, large-sized display glass, etc., may be developed.

(4) Chemical cutting glass

When ultraviolet radiation rays are irradiated on the L^O-A^Oß-SiC^ system

glass containing silver ion, the exposure to light generates a silver colloid.

When heat treatment follows, the silver colloid becomes the crystal core and

crystals of lithium metasilicate are deposited. Because these crystals

greatly lack in chemical durability, compared with the parent glass, and

dissolve in diluted hydrofluoric acid, only the crystallized portion can be

removed. The production process for such a glass is shown in Figure 5. The

chemical cutting glass is used for the printer wire guide, the substrate for

thin-film magnetic head, and as the head for the ink jet printer.

3.4 New Glass Using Biological, Biochemical Characteristics

(1) Biochemical porous glass

A porous glass has fine continuous holes of 1- to 100-nm. The porous glass

developed by the Corning Glass Works in the United States was the first of its

kind in the world. It has been commercialized in Japan.

The porous glass is prepared by utilizing the phase splitting phenomenon of

glass. When a borosilicate glass of a suitable composition is dissolved under

a normal method and reheated after the molding, the glass undergoes phase

splitting and separates into a part rich in SiC>2 and a part rich in B3.

Because the B203-rich part dissolves when treated with acid, a porous glass,

as shown in Figure 6, results.

26
UU light Deposition of

I | "?Bk Li2° *

Si0j crystal

VM vM/x m"^ /

V?

Exposure

i

Chenical

cutting glass

Heat treatment Etching

7LM

(crystalliza- (Hydrofluoric

tion) solution)

(Li2OSi02)

Chenical

cutting

crystallized J | I J 1 UV light

Figure 5.

Heat treatnent Exposure

(crystallization)

(Li20-2Si02)

Manufacturing Process of Chemical Cutting Photosensitive

Crystallized Glass

Na20-B203 Si02 Narrow qn hole ölUa

Unsplit-phase

borosilicate

soda glass

b. Split-phase

glass

c. Porous

silica glass

Figure 6. Preparation of Porous Silica Glass

The biochemical uses of this glass include the segregation and purification of

microorganisms and biochemical matters, and the immobilization of

microorganisms. For example, a column of porous glass can segregate and

purify different size viruses. The use of porous glass as an immobilized

enzyme carrier will probably be put to practical use on a larger scale

27
Generally, enzymes are expensive and it is said that recovery is difficult

when once used and the enzymatic activity often declines. If the enzyme can

be immobilized on the surface of some material and the decline in activity can

be prevented, it will answer the need for reducing the cost of using enzymes.

The organic polymer and porous glass are promising candidates for carriers.

(2) Biological hard-structure glass

Hopes are placed on glass and crystallized glass as materials for artificial

bones and artificial tooth roots. Metals have been mainly used up to now as

hard-structure materials. However, metals do not have a biological affinity

and they are used with the expectation that they will be extracted. Ceramics

such as alumina, etc., are also without a biological affinity, however, they

are warrantable, even when left within a living body, because they are free

from toxicity. However, materials without a biological affinity have the

defect of generating a gap between the peripheral structures and it is

considered that materials with an affinity will become the mainstream.

The biological glass has an Si02-P205-CaO-Na20 system base and a biological

affinity as it resembles the constitutive elements of bones. However, the

strength of the glass is low and it is difficult to put it to practical use.

Therefore, crystallized glass and compounded crystallized glass are being

studied. Crystallized glass with a crystal phase similar to the apatite in

bone and with increased strength due to crystallization, and glass that has

crystals growing in a single direction under stress and provided with the same

structure as fiber-reinforced materials have been developed.

As stated, the biological hard-structure glass is to be used for artificial

tooth roots and artificial bones, and, at present, the only biological glass

that has been put to use is the aural small bone implant. All others are

still in the clinical stage.

BIBLIOGRAPHY

1. Yasui, I. and Kawazoe, H., "High Function Glass," Tokyo University

Publisher's Society, 1985.

2. Kita, H., et al., J. AM. CERAM. SOC, 54, 321 (1971).

3. Oikawa, M., et al., APPL. OPT., 21, 1052 (1982).

4. Moriyama, T., et al., 7th ECOC, Fll (1980).

5. Takahasi, S., OPTICS E, 34, 70, 1982.

6. Miller, S.E., BELL SYST. TECH. J., 48, 2059 (1969).

28
7. Prewo, K.M., et al., J. MATE. SCI., 17, 1201 (1982).

8. Prewo, K.M., J. MATER. SCI., 17, 3549 (1982).

9. Stooky, S.D., IND. ENG. CHEM., 45, 115 (1953).

20158/9365

CSO: 4306/7555

29
ADVANCED MATERIALS

BRIEFS

SUPERCONDUCTING MATERIAL DEVELOPMENT—Tokyo, 4 August KYODO—The Ministry of

International Trade and Industry's Electrotechnical Laboratory said Tuesday it

has developed a new superconducting compound that showed a transition to a

zero-resistance state at 65 C, or 338 Degrees Kelvin. The new superconducting

material, which is an oxide based on strontium, barium, yttrium, and copper,

continued in the zero-resistance state similar to superconductivity for 10

days at room temperature in the air, the laboratory said. The Electrotechnical Laboratory also noted that measurements of the new material allowed

it to observe a nonlinear characteristic curve between current and voltage at

65 C, which is another indication of superconductivity. The research results

of the laboratory's experiments with the new superconducting material will be

published in the August edition of the JAPANESE JOURNAL OF APPLIED PHYSICS.

[Text] [Tokyo KYODO in English 1113 GMT 4 Aug 87 OW] /12232

CSO: 4306/0523

30
AEROSPACE, CIVIL AVIATION

COUNTRY PLANS THREE-AXIS WEATHER SATELLITE

Tokyo AEROSPACE JAPAN-WEEKLY in English 3 Aug 87 pp 5,6

[Text]

Trie Meteorological Agency and the National Space

Development Agency of Japan (NASDA) plan to replace the

spin-stabilization system now used in the "Himawari" series

weather satellites with the three-axis stabilization system

beginning with the fifth weather satellite which is

scheduled for launch in 1993.

The planned new satellite will be supplied by either

Ford Aerospace of the U.S. or Aerospatiale of France. It

will be equipped with two infrared-ray cameras to improve

observation capabilities.

The currently operational nHimawari-3" weather

satellite is basically the same as the U.S.' GOES

(Geostationary Operational Environmental Satellite)

developed by Hughes Aircraft. It is a spin-stabilization

satellite.

Japan plans to launch another spin-stabilization

weather satellite or the "Himawari-4" in August 1989. The

planned three-axis stabilization satellite will be launched

in 1993 as the "Himawari-5." Launching cost is estimated at

¥30 billion compared with ¥22 billion now required for the

conventional spin-stabilization satellite.

/8309

CSO: 4307/033

31
AEROSPACE, CIVIL AVIATION

MOS-1 TO BE LAUNCHED IN JANUARY 1988

Tokyo AEROSPACE JAPAN-WEEKLY in English 3 Aug 87 pp 6, 7

[Text]

The National Space Development Agency of Japan (NASDA)

has announced that it would launch Japan's first remote

sensing satellite called MOS-1 marine observation satellite

on January 23, 1988, from the Tanegashima Space Center in

Kagoshima Prefecture.

The satellite will be equipped with three different

sensors for practical observations of the earth (primarily

the oceans). The sensors include a multispectrum electronic

self-scanning radiometer, a visible and thermal infrared

radiometer and a microwave scanning radiometer.

It will be used to observe water vapor in the

atmosphere, ocean currents, the water surface temperature,

the water-content of clouds, the distribution of ice floes

and of chlorophyl, the generation of red tides, the

detection of mineral and energy resources, crop inventories

and so on.

The observation data will be provided to organizations

cooperating in this evaluation and to overseas earth

observation stations.

The satellite will weigh about 740 kilograms and will

be launched into a sun-synchronous orbit at an altitude of

about 900 kilometers by a two-stage N-II rocket. Its

mission life is two years.

/8309

CSO: 4307/033

32
AEROSPACE, CIVIL AVIATION

H-ll TO BE POWERED BY NEW ENGINE

Tokyo AEROSPACE JAPAN-WEEKLY in English 3 Aug 87 p 7

[Text]

The National Space Development Agency of Japan (NASDA)

has decided to adopt the LE5A new liquid oxygen/liquid

hydrogen engine for the second stage of the H-II nextgeneration large-capacity rocket which will be used in the

1990s.

The new engine is modified from the LE5 engine to be

used in the present H-I rocket. With the enhanced-thrust

engine, the H-Il's launching capacity will be increased by

10%. It will be capable of launching a 2.2-ton satellite

into a geostationary orbit 36,000 kilometers above the

earth.

The LE5 is now being developed by NASDA in cooperation

with Mitsubishi Heavy Industries, Ltd. (MHI) and

Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI).

NASDA plans to use the H-II rocket not only to launch

large-capacity applications satellites but also to deliver

supplies to the space station which will be built jointly by

the U.S., Europe, Canada and Japan.

/8309

CSO: 4307/033

33
AUTOMOTIVE INDUSTRY

DEVELOPMENT, FEATURES OF ROLLER ROCKER ARM REPORTED

Tokyo NAINEI KIKAN in Japanese Jun 87 pp 47-52

[Excerpts] 1. Foreword

In the industrial world recently there has been dynamic progress in lowering

engine friction. There is a high frequency of automobiel use by passenger

vehicle drivers at low and medium engine speeds, and particular attention has

been paid to the fact that the percentage of total engine friction accounted

for by valve train friction is very large in the areas of such numbers of

revolutions. Rollerizing the cam follower is extremely effective as one

method of greatly reducing valve train friction, and the number of places

taking this up as a main theme of development have increased.

Rollerizing the valve train is not a particularly new technology, and it has

been employed in some automobile engines for 20 or 30 years, mainly for the

purpose of dealing with wear on the valve train. Since then, operation of

automobile engines at high speed revolutions has advanced, and with the

accompanying lightening of the valve train and progress in wear-resistant

materials, such technology has disappeared from use,

Mitsubishi Motor Corporation planned a reexamination of this technology and

with full use of both the newest valve train planning technologies and

technology related to complex structures fostered by many years of experience

with aluminum rocker arms, they possess the world's first structure formed

from needle rollers and aluminum rocker arms. Moreover, they successfully

developed a needle roller system rocker arm, which has the same level of high

speed following characteristics of valve trains currently in use, and used it

in the V6 engine with the Debonair model supercharger which went on sale this

spring.

In this article we introduce the special features and structure of the needle

roller arm system rocker arm, and the effect of its use, from the point of

engine friction.

7. Results.

7.1 Practical improvement in fuel consumption.

Figure 13 [not reproduced] shows one example, and at 10 mode fuel consumption

there is an improvement of 3 to 5 percent. For fuel consumption at fixed

34
[teichi Nenhi], especially at low speeds, the effect is large and there is a

big improvement of from 2 to 8 percent. In idle fuel consumption there are

also cases not linked to improvement in fuel consumption where the percentage

of friction lowered is unchanged due to deterioration in combustion because of

choking off fuel and increased pumping loss due to closing the open throttel,

etc. This point also confirms that it will be advantageous in diesel engines

which do not have throttle valves.

Besides this, using a cam with smaller overlap on the valve timing and also

combining that with engine modifications such as lowering the number of idle

revolutions, results in a multiplication effect and a further large increase

in 10 mode fuel consumption becomes possible.

7.2 Improvement in passing acceleration performance.

Engine full open performance is increased by friction reduction due to the

needle roller system rocker arm, and generally low and medium speed torque

increases from 1 to 3 percent. In terms of the effect on running efficiency

of the vehicle, this is especially manifest in an improvement of passing acceleration.

Figure 15 [not reproduced] shows examples of improvement in passing acceleration, and the improvement is from 3 to 5 percent, and on the practical side,

this is a big effect. The feeling is a light, pleasant sensation like being

lofted up. Furthermore, that this sensation can be most strongly felt when

racing is extremely natural, because as shown in Figure 8 [not reproduced] the

reduction rate of engine friction is linked to the load reduction rate.

7.3 Improvement in valve train wear resistance.

In spite of the fact that the contact surface pressure between the cam rollers

increases, wear resistance increases dramatically due to rolling contact in

the needle rocker system and thus contributes to longer engine life. The results of simulated accelerated wear experiments are shown in Figure 16 [not

reproduced] for a gasoline engine and in Figure 17 [not reproduced] for a

diesel engine and we see that they surpass by far even those for the ceramic

chip which we developed earlier. This accelerated wear experiment is one method

where we can discern clearly the anti-scuffing qualities of the slipper system,

and in the needle roller system which changed from sliding contact to rolling

contact, we need not worry about this point, and the results were forecast from

the start. However, with the needle roller system, because full validation of

pitching resistance is required especially, we also carried out anti-wear

characteristics confirmation experiments in the high revolutions zone too.

Representatively, at 6,000 rpms which is an approved number of revolutions for

the engine, even in lengthy experiments of 1,500 hours we confirmed no problems

in roller revolutions whatsoever.

7.4 Other effects.

Reducing valve train friction has many other merits in addition to improving

performance and fuel consumption. For example, vibration of the timing belt

35
due to the resonance of the belt is an abnormal sound and this occurs when the

actual tension of the belt is fairly high, but since valve train working torque

is reduced by rollerization, actual working tension is reduced by this amount

and it is harder for these sounds to occur. Accordingly, the degree of freedom to set tension range in assembly is increased.

Furthermore, cranking torque declines when starting the engine, and improvement in startability was also confirmed with diesel engines.

Besides these we want to add also that at the same running resistance, because

engine load declines, waste gases (especially NOx) and lowering of combustion

noises also result.

12964/9274

CSO: 4306/6073

36
DEFENSE INDUSTRIES

JAPAN, U.S. AGREE ON SDI RESEARCH

Tokyo AEROSPACE JAPAN-WEEKLY in English 3 Aug 87 p 5

[Text] Japan and the U.S. reached agreements July 22 on the framework for

Japanese participation in the U.S. Strategic Defense Initiative (SDI) Research

Program. The agreements were signed by U.S. Defense Secretary Caspar Weinberger

and Japanese Ambassador Nobuo Matsunaga at the U.S. Department of Defense.

The agreement consists of two documents. The Japanese government, however,

released the basic conditions of the Japanese participation only and refused to

release the rest which features an undisclosed arrangements for implementing

the framework agreement.

According to the government, Japanese corporations and other entities participating in the SDI research will be allowed to incorporate the research results

in their own products royalty-free even though the patents will generally

belong to the U.S. government.

However, utilization of the new technology and information classified for

military reasons will be restricted. And such classified technology and

information will be designated by the U.S.

Under the agreement, Japanese entities—corporations and governmental research

bodies—will be treated on equal terms with U.S. competitors in the bidding

for contracts. Japanese corporations will be eligible to bid directly on

contracts supplied by the Pentagon or its prime contractors.

Japanese participants, however, will be required to protect military technologies developed through the research in accordance with existing Japanese

laws as well as the present Mutual Defense Assistance Agreement between the

two countries.

Japan is the fifth country which signed a government-level agreement on SDI

participation, following the U.K., West Germany, Israel and Italy. France,

Belgium, the Netherlands and Canada will participate on a commercial basis.

/8309

CSO: 4307/033

37
DEFENSE INDUSTRIES

XSSM-1 PROVING EXCELLENT PERFORMACE IN U.S.

Tokyo AEROSPACE JAPAN-WEEKLY in English 3 Aug 87 pp 4, 5

[Text] The XSSM-1 surface-to-ship missile developed by the Technical R&D

Institute (TRDI) for the Ground Self-Defense Force (GSDF) is now proving its

excellent performance in the United States.

The missile has been undergoing operational tests since late June at a test

range in the United States. According to the Defense Agency (JDA), the missile

succeeded 100% in hitting the target in all tests made so far, including the

maximum-range test and an ECM (electronic countermeasure) test.

The XSSM-1 is now highly evaluated by U.S. military

officials concerned as one of the best missiles in the

world.

The XSSM-1 is a derivative of the Model 80 ASM-1 airto-ship missile. The missile development is underway with a

view to deployment at operational units in FY 1988.

Mitsubishi Heavy Industries, Ltd. (MHI) has been promoting

the development program as the prime contractor in

cooperation with other electronics manufacturers.

The missile is powered by a solid rocket motor combined

with a small jet engine. Its guidance system is a

combination of the inertial guidance at the initial stage of

the flight and active radar homing at the last stage.

It is five meters in overall length, 0.35 meters in

diameter and it weighs 660 kilograms. Development cost is

estimated at ¥24 billion. GSDF plans to procure the XSSM-1

missiles for 3.5 squadrons or 56 launchers under the current

FY 1986-90 Medium-Term Defense Buildup Program.

/8309

CSO: 4307/034

38
DEFENSE INDUSTRIES

DEFENSE AGENCY OFFICIALS DIVIDED ON FSX PLAN

OW151351 Tokyo KYODO in English 0917 GMT 15 Aug 87

[Text] Tokyo, 15 August KYODO—A plan to jointly remodel an existing U.S.

fighter with a U.S. company for Japan's next generation support fighter, known

as the FSX, has a strong possibility of being adopted, defense agency sources

said Saturday.

But the air staff office of the Air Self-Defense Force, which calls for

domestic development of the FSX, opposes the remodelling plan, according to

the sources.

McDonnell Douglas' F-15J, the ASDF's mainstay interceptor fighter, which is

being licence-built in Japan with Mitsubishi heavy industries as the prime

contractor, is the most likely candidate, the sources said.

The Defense Agency will begin development of the FSX from fiscal 1988,

starting next April, and will appropriate about 70 billion yen for the

development cost of the FSX during the five-year defense buildup program which

started in fiscal 1986, the sources said. The Defense Agency will make a

final decision on the selection of the FSX after a prototype test flight in

seven or eight year's time, they said. The Defense Agency is considering

whether the FSX should be developed domestically or jointly with the U.S.

aerospace industry, or imported.

General Dynamics' F-16 and McDonnell Douglas' F-18, as well as the F-15, are

also among the candidates.

Meanwhile, a Japanese consortium, led by Mitsubishi, has called for domestic

development of the FSX, to be the successor to the F-l support fighter, which

is to be phased out in the 1990s.

U.S. Secretary of Defense Caspar Weinberger proposed on a visit to Japan in

June should buy an American warplane or remodel a U.S. aircraft in line with

Japanese technology in selecting the FSX.

The U.S. Senate adopted a resolution in July which urges the U.S. Government

to press for a commitment from Japan to procure a U.S. fighter for the FSX.

39
Senator John Danforth, a proposer of the resolution and a Republican from

Missouri, where both McDonnell Douglas and General Dynamics are located, said

"if the Japanese proceed to develop and build their own jet fighter, it will

belie all Japanese claims that they wish to rectify the current trade

imbalance."

/12913

CSO: 4307/032

40
DEFENSE INDUSTRIES

FS-X EXPECTED NOT TO BE UPSET BY SENATE RESOLUTION

Tokyo AEROSPACE JAPAN-WEEKLY in English 3 Aug 87 pp 1, 2

[Text]

The U.S. Senate, acting on an omnibus trade bill,

passed on July 21 a resolution under which the U.S.

government is required to press for a commitment from Japan

to purchase American aircraft as the FS-X next support

fighter of the Air Self-Defense Force (ASDF).

The resolution which was passed unanimously by 97

Senators has no bidding force but it was added as an

amendment to the trade bill which was voted and passed by

the Senate on July 22.

The resolution was proposed by Democratic Leader Robert

Byrd and Sen. John Danforth. It calls for continuously

pressing Japan to purchase American aircraft. The U.S.

Department of Defense is also required to report to the

Congress on the FS-X negotiations with the Japanese

government.

Commenting on the Senate resolution, the Japanese

Defense Agency (JDA) officials said, "Japan would make its

own decision on the FS-X. This is a major premise."

They stressed that the aircraft selection would be

pursued based on the three principles Worked out by JDA

Director General Yuko Kurihara, which call for: 1)

selecting the best aircraft from purely a military point of

view; 2) gaining consensus of the Pentagon on the basis of

the importance of the Japan-U.S. Security Treaty; and 3)

ignoring pressure from the defense industries of both

countries.

The Japanese industries concerned expect the FS-X to be

a domestic development effort whether or not the omnibus

trade bill should be passed. They strongly expect the

41
Japanese government to select an indigenous aircraft because

Japan's future aircraft development capabilities would stall

if American aircraft should be selected.

Mitsubishi Heavy Industries, Ltd. (MHI), Japan's

leading defense contractor, refrained from commenting on the

Senate resolution on the FS-X. But MHI have reiterated its

view that Japan ought to defend itself with its own weapons.

Quite a few engineers involved in the FS-X development

will retire under the age limit. If research and

development activities of domestic aircraft should be

interrupted as a result of introduction of U.S. aircraft,

there would be no engineers who take over the accumulated

technology, according to MHI.

The Japanese aircraft industry insists that the

Japanese government should not be swayed by the Senate

resolution in making the FS-X decision.

/8309

CSO: 4307/034

42
DEFENSE INDUSTRIES

PROSPECTS FOR CEILING ON DEFENSE BUDGET PROPOSAL

Tokyo AEROSPACE JAPAN-WEEKLY in English 3 Aug 87 pp 2, 3

[Text]

The budgetary ceiling on the FY 1988 defense budget

proposal will be somewhere between 6.5% and 7.0% in terms of

a growth rate from the current fiscal year's budget,

according to the negotiations between the Defense Agency

(JDA) and the Ministry of Finance.

JDA wants a 7.3% or at least 7.0% increase in the

defense spendings for FY 1988 in order to stably implement

its FY 1986-90 Medium-Term Defense Buildup Program (MDBP).

However, the value of yen against dollar remains

stronger compared with the yen value when the FY 1987 budget

was compiled. In addition, the amount of money earmarked

for sales tax in the FY 1987 budget is unnecessary in the FY

1988 budget. Because of such restraining factors, a final

decision on the ceiling will be made through ministerial

negotiations between JDA Director Yuko Kurihara and Finance

Minister Kiichi Miyazawa.

Negotiations for the budgetary ceilings on the FY 1988

budget proposals got into upswing after the supplementary

budget bill passed the Diet on July 24. The Cabinet is

expected to decide on the ceilings by July 31 at the latest.

JDA has insisted on a 7.3% increase in defense budget

before full-scale negotiations begin because it has to

assure at least 5.4% real growth every year in order to

carry out the current MDBP which calls for spending a total

of ¥18,400 billion.

According to an economic survey, the deflator for FY

1988 is estimated at 1.9. So, to assure a 5.4% real growth

rate, JDA needs a 7.3% increase in consideration of the

deflator. The increase is equivalent to addition of over

¥250 billion to the initial defense budget (¥3,517.4

billion) for FY 1987.

43
In addition to those macroeconomic figures, JDA is

aware of other restraining factors. One is strong yen.

When the FY 1987 budget was compiled, the amount of military

equipment imports were converted into dollars at an exchange

rate of ¥163 per dollar.

Though recent exchange rates of yen are heading a

little downward, the yen value still remains higher than

¥163 per dollar. No decision has been made on a new

exchange rate to work out the ceiling on the FY 1988 budget

proposal.

But it will certainly be higher than ¥163. As a

result, the amount of equipment imports in yen would be

smaller, restraining an overall growth rate of the budget.

The growth rate will also be lowered because no funds

are necessary for sales tax in FY 1988. When the FY 1987

defense budget proposal was compiled, some ¥9.3 billion was

set aside for the sales tax. If the sales tax was

introduced as the government had planned, the FY 1988 budget

was to include ¥50 billion for the sales tax.

Since no decision has been made yet on any indirect

taxes, JDA cannot appropriate any funds for such taxes

instead of the sales tax. So, the budget will have to be

scaled down in this respect too.

JDA was allowed to ask for a 6.3% increase in its

budget proposal under the FY 1987 budgetary ceiling. As the

government will relax the ceilings on budget proposals in

general with a view to expanding domestic demand, the

ceiling on the FY 1988 defense budget proposal will likely

be higher than 6.3%

/8309

CSO: 4307/034

44
DEFENSE INDUSTRIES

ASDF TO SELECT AFIS IN AUGUST

Tokyo AEROSPACE JAPAN-WEEKLY in English 3 Aug 87 pp 3, 4

[Text]

The Air Self-Defense Force (ASDF) plans to introduce an

automatic flight inspection system with about ¥900 million

authorized under the FY 1987 budget for installation on the

YS-11 flight checker.

Selection of the system is now underway with proposal

received from C. Itoh & Co., Ltd. (representing Litton

Systems Canada), Nozaki & Co., Ltd. (Sierra Research),

Nissho Iwai Corp. (Gull) and Furuno Electric Co., Ltd. A

final decision on the selection is expected to be made in

August this year.

ASDF plans to modify two of the eight YS-11 transport

aircraft into flight checkers. In addition to a YS-11

flight checker now in service, the two aircraft will also be

equipped with AFIS.

The first of the two aircraft will be modified in FY

1987-89. Following the authorization of the funds for AFIS,

ASDF will ask for the aircraft modification funds under the

FY 1988 budget.

/8309

CSO: 4307/034

45
DEFENSE INDUSTRIES

BRIEFS

ASTRONOMERS OPPOSE SDI—Tokyo, 13 August KYODO—A group of noted Japanese

astronomers Thursday issued a joint statement opposing the U.S. strategic

defense initiative (SDI) project. The statement said the project restricts

the launching of scientific observation satellites and classifies technology

and data obtained from research for military reasons. The SDI project not

only betrays the wish for peaceful utilization of space, but hampers progress

in astronomical studies, it said. The ^statement also said 510 astronomers who

signed it would not participate in any research related to the project. The

astronomers, at 70 organizations across Japan, account for three-fourths of

scholars in this field in this country, the promoters said. The 29 promoters,

including director Yoshihide Kozai and professors Masaki Morimoto and Jun

Jugaku at the Tokyo astronomical observatory, said the signatures were

collected since last March. Jugaku emphasized the SDI project runs counter to

international cooperation vital for astronomical progress. Moritomo said he

and his group members would appeal to researchers abroad for support for their

cause. [Text] [Tokyo KYODO in English 1256 GMT 13 Aug 87 0W] /12913

CSO: 4307/032

46
ENERGY

SYNCHROTRON RADIATION DEVELOPMENT STATUS REPORTED

Tokyo TOSHI KEIZAI in Japanese Nov 86 pp 46-47

[Article by Yuuta Sagara, scientific journalist, "Synchrotron Radiation"]

[Text] Applicable in Various Academic Fields

Synchrotron radiation (SR) is indispensable for developing next-generation

high-technology such as ultra-large-scale integrated circuit (ULSI), etc., and

has come into the limelight as a new scientific and technical advocator.

SR is electromagnetic radiation generated when positive electrons or electrons

with a velocity close to the velocity of light pass through a magnetic field.

This light possesses the following excellent features: 1) it has a continuous

spectrum extending from far infrared rays to X-rays, 2) it is extremely

strong, 3) it is highly directive, and 4) it has a repeated pulse light with

a short width. There is no light source which can be compared with SR,

particularly in extreme wavelength areas with short waves.

For these reasons, SR is used academically in various fields such as

semiconductor engineering, metallic engineering, industrial chemistry, global

science, medicine, and life science as well as basic physics and chemistry.

It is anticipated that SR will be used in Japan's favorite semiconductor

industrial fields, such as analysis of very small amounts of light elements,

photochemical reactions, surface and interfacial analysis, ultra-fine

processing work, etc. The number of researchers in SR science has increased

sharply.

The United States, West Germany, France, and other countries, are

enthusiastically developing SR facilities. In Japan, the National Laboratory

for High Energy Physics (NLHEP) of the Ministry of Education, Culture, and

Science, the Electrotechnical Laboratory of MITI's Agency of Industrial

Science and Technology (AIST) Nippon Telegraph and Telephone Corporation (NTT)

Atsugi Laboratories, and the Science and Technology Agency (STA) are

developing or are planning to develop such SR facilities. Also, Sumitomo

Electric Industries, Ltd., Mitsubishi Electric Corporation (MEC), Toshiba

Corporation, Shimadzu Seisakusho, Ltd., and the Japan Steel Works, Ltd. are

conducting private research and development of SR facilities with cooperation

from the Ministry of Education, Culture, and Science and MITI.

47
In Japan, the only SR facility with a capacity of 2.5 billion eV is presently

being operated full scale at NLHEP, at Tsukuba in Ibaraki Prefecture. In the

beginning this SR facility had a poor image, being used in research on

physical properties in which an electron accelerator is needed, but it now has

more than 8,000 users annually and is being worked to capacity.

Accordingly, in the next fiscal year, NLHEP will begin development of the

world's most intensive SR light source by using an accumulating ring (AR),

"Incident Storage Ring" of a macro-particle accelerator, "Tristan (electron

and positive electron collision type accelerator)." The Tristan is currently

under construction in NLHEP. NLHEP will carry out this development work so it

can begin conducting experiments on the SR light source in 1989. The

development cost is approximately Yl billion.

The Tristan consists of a 400 m long linear accelerator, an AR with a diameter

of approximately 100 m, and a main ring with a diameter of approximately 1 km.

The AR is a linear accelerator, and further accelerates electrons and positive

electrons accelerated up to 2.5 billion eV, stores them, and sends them to the

main ring.

World's Highest Technology and Large-Scale Optical Plant Is Constructed

SR is radiated when electrons and positive electrons go round the AR. This

type of SR is used in the NLHEP project. When an AR is used, electrons and

positive electrons can be accelerated to the world's most intensive level,

which 6 to 8 billion eV.

SR emitted when using the AR is light from ultraviolet rays to gamma-rays; Xrays with a wavelength of 1 to 0.5 angstrom (1 angstrom is one-hundred

millionth of a centimeter) is the most intensive in such an SR. It is said

that the brightness will be 1,000 to 10,000 times that of the SR facility with

a capacity of 2.5 billion eV.

SR is an important, indispensable weapon in the development of nextgeneration high technology for the 21st century. Accordingly, the STA will

construct a large-scale optical plant in the Kansai district. This plant

consists chiefly of an SR facility which can emit X-rays with a short

wavelength of 0.1 angstrom, which is the highest level in the world.

According to this plan, the STA will construct a ring shaped-accelerator at a

cost of about Y60 billion, with a completion date in 1994. This accelerator

has a diameter of approximately 400 meters, and can emit an energy of

6 billion eV.

Unlike NLHEP's AR, STA's accelerator has great power. On the other hand,

NLHEP's AR is capable of being used for multiple purposes, and will play a

role as a "connection" until the completion of STA's optical plant. Results

obtained form this AR will be fully utilized in the construction of the

optical plant.

In the optical plant the SR can easily be changed from the wavelength of

ultraviolet rays to X-rays. In addition, it can emit light which is 10,000 to

48
1 million times brighter than that of X-ray is generated for medical

examinations.

The shorter the X-ray wavelength, the more possible it is to closely

investigate physical phenomena to carry out super-fine processing work. it

will be possible to use SR in various fields, such as to catch the movement of

electrons acting in crystals, clarification of changes of movement of

molecules in the muscles of animals, development of new semiconductor

processing technologies, and so on.

The STA intends to construct not only the world's highest level SR facility,

but also research facilities which will employ laser light, etc., in the

optical plant. The STA also wants to develop the optical plant as a mecca for

worldwide optical science, and is planning to promote basic research work for

the 21st century through joint use among industry, government, universities,

and international cooperation.

Powerful for Development of VLSI

The scale of facilities will inevitably be large, because the STA's optical

plant and the NLHEP's AR will be used for multiple purposes on a large scale.

In addition, the Electrotechnical Laboratory at Tsukuba is presently

developing a small SR unit to be used industrially even in the clean rooms of

semiconductor plants in the future.

The Electrotechnical Laboratory has already succeeded in accumulating

electrons from a small test ring, and has confirmed synchrotron orbit

radiation (SRO). However, in order to make a small industrial SOR unit, it is

necessary to research and develop well-balanced elemental technologies. For

example, it is necessary not only to miniaturize the electron accumulating

ring, but also to miniaturize electron incident equipment, to enhance the

efficiency of this equipment, to miniaturize beam lines employing SOR, and so

on.

For this reason, the Electrotechnical Laboratory is conducting research on the

small SR in collaboration with Sumitomo Electric Industries, Ltd., MEC,

Toshiba Corporation, and Shimadzu Seisakusho Ltd.

It is expected that a small industrial SR will be fully utilized specifically

to develop ULSIs with an integration degree of more than 64 megabits. In

order to develop such ULSIs, it is necessary to reduce the minimum line width

of circuits transferred to semiconductor wafers to less than 0.5 micron

(1 micron is one-thousandth mm). This is because X-ray lithography employing

a small SR unit is indispensable for achieving this superfine processing

technology.

NTT Atsugi Laboratories are also carrying out the same research and

development work as that mentioned above.

20143/9365

CEO: 4306/2534

49
LASERS, SENSORS, OPTICS

DEVELOPMENTS IN OPTICAL SENSOR TECHNOLOGIES DESCRIBED

Tokyo OPTRONICS in Japanese Dec 86 pp 74-80

[Article by Tatehiko Hidaka, High Frequency Research Office, Electrotechnical

Laboratory: "Development of Hollow Optical Fibers; Establishment of

Micropower Precision Measuring Technology"]

[Text] As lasers diffused, microgas analysis technology utilizing their

excellence in spectral purity and coherence has been developed in recent

years. The current project also tackled the development of high sensitivity

gas analysis technology utilizing so-called hollow fibers in the infrared and

the ultraviolet soft X-ray areas. Initially, hollow fibers for the medium

infrared area 910 ym band) and then experiments of hollow fibers for soft Xrays (25-75 Ä) were made. Since sensor technologies need precision measuring

technology for micropower, the current project has studied and established

precision light attenuation measuring technology using an acousto-optic

element. These technologies are likely to be integrated to contribute to the

progress in new optical sensor technologies in the future.

Introduction

Along with improved functions and reduced prices of various lasers, especially

semiconductor lasers, the development of new sensor technologies combining

them with optical fibers has become active. The current project has also

developed every sort of sensor technology for use in oil refineries. The

Electrotechnical Laboratory has decided to start research into optical sensor

technologies combining an optical fiber and laser as well.

The first theme of the optical sensor technology development by the Laboratory

is the gas analysis technology using a hollow optical fiber. A laser is an

extremely suitable illuminant for detection and determination of a trace of a

gas molecule due to its intensity and monochromaticity. As for its

monochromaticity, for example, it is not impossible to obtain a high-purity

illuminant with a bandwidth of 1 KHz. The gas molecule detection technology

using such illuminants is very likely to be an epoch-making detection

technology whose detection limit exceeds that in the conventional gas

detection technology by several digits.

On the other hand, the Electrotechnical Laboratory has so far pointed out the

potential of the hollow optical fiber based on an entirely new principle; a

50
certain type of glass (quartz, etc.) allows the real part nr of its refractive

index to be smaller than 1 in the infrared area (wavelengths of 9-10 ym) and

soft X-ray area, so that a refractive index of the glass part (clad) of a

hollow waveguide made of such a material, when its hollow part is regarded as

its core, becomes smaller than that of the core, and thus electromagnetic

waves existing at the core will be transmitted without appreciable loss. If a

gas containing objective gas molecules flows into such a hollow optical fiber

and, at the same time, such a laser beam as absorbed by the molecules is

guided and its transmission factor is largely affected by the presence of gas

molecules, thereby permitting molecules to be detected. Based on this

concept, the Laboratory decided to initially start with research into test

manufacturing and characteristic evaluation of a hollow optical fiber in the

infrared and the soft X-ray areas.

In addition, the second theme of the optical sensor technology development is

the development of a precision measuring technology for microoptical power

needed for the test and evaluation of fundamental characteristics of optical

sensors. The research aims at precise measurement of micropower of below yW,

using a method to measure the power ratio with existing laser small power

measured values as its standard. Measurement by this method requires

measuring precise power ratios (attenuation) and an optical attenuator to

materialize laser beams with the power ratios measured. This article

describes the development of two types of methods effectively utilizing

characteristics of the acousto-optic modulator for the former and, for the

latter, test manufacturing and a study of a precision optical attenuator using

a deflecting plate permitting correct theoretical values to be obtained.

Development of Hollow Optical Fibers

Infrared-Area Hollow Fiber

Transmission wavelengths of conventional quartz (SiÜ2) optical fibers roughly

range from 0.3 ym to 2 ym. Transmitting laser beams with outside wavelengths

of them necessitates a newly devised transmission guide made of materials

other than Si02 or having different structure based on an entirely new

principle. Of them, optical fibers made of new materials, notably KRS-5,

etc., have been studied as core materials for infrared transmission, research

and development going on in the current large project as well.

Generally speaking, a refractive index of solids (including glass) is likely

to become smaller than the value of vacuum or air (1.0) in the infrared and

the vacuum ultraviolet soft X-ray areas. Figure 1 shows typical complex

indexes of refraction of a solid in from the infrared to the vacuum

ultraviolet areas. The real part of a complex index of refraction becomes

smaller than 1 in the infrared area due to the resonance to lattice vibration

of a solid and in the vacuum ultraviolet area due to plasma vibration of

electrons inside of the solid. If a solid with a refractive index smaller

than 1 (glass with a smooth surface is preferable) is available, a step index

type optical fiber can be configured by using material such as a clad

material. A core is a hollow part (vacuum or air). This article reports a

hollow waveguide for infrared light (especially 10.6-ym (CO2 gas laser beam).

51
- lOOOA

Figure 1. Solid Complex Indexes of Refraction; nr-iK

In the infrared and the vacuum ultraviolet

(soft X-ray) area, nr can be smaller than 1.

2000 1800 1600 1400 1300 1000 800 600 400 250

Wavenumber (cm-1)

Figure 2. nr-iK of Quartz (Si02) and Ge02 in the Infrared

Area (adjacent to 1,000 cm"1= 10 ym)

With GeO2nr falls to 0.3 at 940 cm"1.

Figure 2 shows complex indexes of refraction nr-iK (nr and K representing a

real and an imaginary part, respectively) of Si02 (quartz) and Ge02, a similar

glass material, which are the most fundamental as glass materials. In the

drawing, Ge02 glass shows its nr being smaller than 1 at 940 cm"1(10.6 ym).

As against this, with Si02, nr becomes smaller than 1 only within the range of

1030-1300 cm" 1, showing no effect to a C02 gas laser beam (940 cm"1-

10.6 ym) . For this reason, it was decided to start with Ge02 for an optical

fiber material for C02 gas lasers.

Figure 3 shows contents of K2O and ZnO and then optical characteristics

(minimum loss wave numbers of a hollow optical fiber and then loss values).

Loss of 0.05 dB/m can be expected with a 1-mm-aperture linear fiber. Figure 4

shows loss characteristics when a C02 gas laser beam is actually transmitted.

Transmission loss actually obtained is about one digit less compared with a

theoretical value, which was presumably caused by an imperfect internal

surface of the hollow fiber or the core-clad interface. It was proven that in

manufacturing the hollow fiber, a microcrystal of Ge02 grew with ZnO as its

core to aggravate its characteristics. A study of its improvement including

material composition, is underway at present.

52
Figure 3. Transmission Characteristic (Theoretical Value) of Ge02-K20-ZnO

Glass Hollow Fiber

Values to 1-mm aperture-HE^ mode

Numerics on either side of the triangle represent mol

concentrations of Ge02. One division of the horizontal axis

corresponds to 10 mol concentration of ZnO and K2O, those

closer to the right side show higher K2O concentrations.

Solid lines show wave numbers indicating minimum loss, while

dotted lines show then loss (db/m).

80GeOi-10ZnO 10K,O

Experimental

"00 1050 100U 950 900 850

Wavenumber (cm"')

Figure 4. Transmission Characteristics of 80GeO2-10K20-10ZnO Glass Hollow

Optical Fiber

Experimental values and theoretical estimated values

53
X-Ray Transmission Fiber

In general, with a solid the real part nr of its refractive index becomes

smaller than 1 in the vacuum ultraviolet X-ray area (wavelength of below 1,000

A). In frequencies much higher than plasma vibration (wavelength of about

1,000 A) of electrons inside of a solid, nr and K can be supported by

nr- 1 —2"(a>p/(ö):

K-y(&)p/o))3 • l/(<y„r)

where wp and T represent electron plasma frequency and its relaxation time,

respectively. Figure 5 shows nr-iK, complex indexes of refraction of quartz

(Si02) in the soft X-ray area (100-10 Ä) . The nr value is, for example, 0.99

at 50 A, a value usable as a clad material for hollow optical fibers.

However, the value of loss term being too great to override mainly contributes

to increasedQ loss against fiber bending. In Figure 5, the peak and nr curve

seen at 23 A are caused by the absorption of inner electrons by the oxygen

atom.

1.0

0.98

0.96 -

10-

20 30 50

Wavelength (A)

100

Figure 5. nr and K of Quartz (Si02) in the Soft X-ray Area

The X-ray transmission fiber efficiency may be evaluated as follows: Suppose

a case where X-ray's advance direction is curved 90 degrees; 45 degrees

incidence using a quartz plate results in a reflectance of 10"^ percent,

54
proving no practicability. As against this, a quartz hollow fiber

theoretically shows that its transmission efficiency can exceed 1 percent.

Thus, expectations are placed on a hollow optical fiber for its excellent

efficiency 104times that of a plane reflecting mirror in 90-degree curving.

Soft X-ray transmission characteristics of a quartz hollow fiber were obtained

as follows: A block diagram of the experiment is shown in Figure 6. The

illuminant was an SOR facility installed by the Electrotechnical Laboratory,

which was made monochromatic by the oblique incident diffraction grating

spectroscope. For improved spectral purity, a proper filter was used. A soft

X-ray made monochromatic is let into the quartz hollow fiber with an internal

diameter of 0.2 mm<f> and total length of 230 mm to be transmitted. An

outgoing X-ray is detected by the ceramic channel thoron. Electric generating

power from the channel thoron is amplified, processed by the multichannel

analyzer, and then followed by data processing. The fiber input terminal is

fixed and it is parallel to an incident beam. The outgoing terminal, together

with the detector, rotates up to 90 degrees against the incident direction,

when the fiber draws a uniform arc of circle through the total length. Figure

7 shows an example of transmission efficiency thus obtained. The

characteristics qualitatively tend to be in accordance with their theoretical

values, but the efficiency as a whole is one digit poorer. This means to

steam from the fiber direction at the input terminal being slightly deflected

from the X-ray beam direction. Angle fitting at the incident part is so

severe as to be within 0.2 degrees. Considering that angular (sysmach) of the

incident part is subtracted, transmission efficiency roughly accords with its

theoretical value.

Shielded roan aeteotot

pouer

souroe

Filter ; Fiber

T

L

-3

Deteotor

1

Rotary

table

Hultiohannel

analyzer

Figure 6. Block Diagram for Soft X-ray Transmission Characteristic

Measurement

Figure 8 shows wavelength dependency of transmission efficiency when the angle

is made constant. Although fine ripples are present, appreciable wavelength

dependency cannot be found as a whole. Loss is great for wavelengths shorter

than 25 Ä, which is attributable to the absorption (K absorption) of oxygen

inner-shell electrons in Si02. Also, the weak peaks adjacent to 40 A are

presumably ascribed to the influence by the absorption (43.5 A) of innershell electrons of carbon C on the internal surface of the hollow fiber.

55
Calculated

S?

0 10 20 30 40 50 60 70 80 90

Curvature angle ^ (deg)

Figure 7. Angular Dependency of Transmission Efficiency

The upper results are for 32 Ä and the lower for 68 A.

10

^

§

o.v

</>=0'

<&=45*

^=90*

20

—I30—r40

—T50—I—

60

"~i—

70 80

Wavelength /< (A)

Figure 8. Wavelength Dependency of Transmission Efficiency

Micropower Precision Measuring Technology

Power Ratio Measuring Method Utilizing Acousto-Optic Modulator

For the measurement of laser beam power ratios and attenuation, a method

involving utilizing photodiodes and pyro-electricity elements is available,

substituting the power ratios, etc. for voltage ratios of dc and audio

56
frequencies, and thereby permitting their measurement. For the measurement of

relatively great power ratios, however, two types of methods have been newly

developed which utilize typical modulation characteristics such as frequency

deflection and spatial modulation of an acousto-optic modulator. Both of them

use a 30 MHz attenuation measuring device already developed.

Modulated Power Substitution Method

1. Principle: AOM's linear modulation characteristics are utilized. In AOM

driven by a sine wave is ample diffracted light, while I1( the intensities of

the primary diffracted light in the Raman's area and the Bragg area can be

expressed respectively as follows:

I,=J,2(hAn) =-|-(hAn)2-^(hAn)4+

Ii = sin2 (h'An) = (h'An)2-j(h'An)4+

(1)

(2)

where J]_, h and h' and An represent a primary Bessel function, constants and

variations of the refractive index. When (h n) is small enough compared with

1, Ii is proportional to (An)2. When LiNbC>3 is used as an electro-acoustic

sensing element for AOM, n is proportional to ac modulated voltage E, so that

I]_ is proportional to E* or modulated power. Therefore, variation ratios of

I]_, a laser beam intensity, can be substituted for modulated power.

2. Experience: Figure 9 shows the circuit for the experiments. A laser beam

(He-Ne, 633 nm) goes into AOM driven by 30 MHz modulated power controlled by

the high frequency attenuator, and its primary diffracted light is received by

the photo detector through the photo attenuator. Thirty MHz is chopped by 1

KHz to facilitate detecting laser beams, while the intensity of a received

beam corresponds to the magnitude of a 1 KHz signal of the photo detector's

output, thereby permitting the magnitude to be observed by the synchronism

detector. When the attenuation of the photo attenuator changes, changes in

the output beam intensity are measured by regulating AOM modulated power by

the high frequency attenuator so as to constantly maintain the same indication

of the synchronism detector and by reading a then variation ratio of modulated

power by the 30 Mhz attenuation measuring device.

Laser

nooustooptio

nodulator IV

Photo

attenuator

Photo

detector

High

Frequently

attenuator

30 HHz attenuation

neasurlng deuioe Synohranisn

detector

30 HHz

asolllatar

SiSL Pulse

oscillator

JVL

Figure 9. Laser Beam Power Ratio Measuring Circuit by Modulated Power

Substitution Method

57
To know the proportional relation between 1^ and Yr, a comparison was made by

measuring the same attenuation with various AOM drive voltages with the result

shown in Figure 10. The experiment used AOM for use in the Raman's area,

while the calculated value was obtained by the expression (1). A range of

about 50 dB was obtained for the deviation of ±0.1 dB.

' '»

1

Hamsurcd

r i 1 "

0.3

Caloulated

ixprmion

value

(1)

by

_

0.2

0.1

^* i T

I 1

0.0 s 1 i

-0.1 - -

-0.Z -

-0.3

i 1 |, 1

10 1 10 -'

Hod

1 1

ulttid

1

voltage (V

. .1 1 1

-10 -20 -30 -40 -50 -60 -70

Prinary diFFraoted light intensity (dBB)

Figure 10. Experiment on I^-E^ Relation

Intermediate Frequency Substitution Method

1. Principle: This method was used in microwave bands, etc. but had not been

developed in the optical area. It includes the serial and the parallel

methods. Figure 11 shows the serial method. With the use of AOM's frequency

deflection characteristics, a required difference frequency laser is made.

Laser output is divided into a local and a measuring channel, with the former

modulated by AOM driven by sine wave modulated voltage. The primary

diffracted light is output at an angle of ]_ with its frequency deviating by

30 Mhz. This beam is synthesized with a local channel beam with the original

frequency through the photo attenuator. The synthesized beam is detected by

the photo detector and then by the intermediate frequency detector to fetch

intermediate frequency of 30 MHz. At this time, the transmission factor of

intermediate frequency signal power and that of the photo attenuator are

proportional to each other in the scope where the beam intensity of the

measuring channel is proper. Intermediate frequency signals go into the

intermediate frequency level meter through the intermediate frequency

amplifier and the standard attenuator. Photo attenuation can be measured by

regulating the standard attenuator to enable this level meter instruction to

be constant. With the parallel method, noise effects by the photo detector,

etc., can be controlled with the use of a switch by inputting photo detection

output and the standard attenuator output alternately into the intermediate

frequency amplifier to detect synchronism.

58
V

Laser

Local channel

Measuring channel

VJ ACDUEtO

optic

nDdulatDi

u

[nternediati

frequency

»cillator

/

Photo

attenuator

\

V

Photo

detector

Intarnadlata

frequency

leuel neter

Intarnadlata

Fraquancy

standard

attenuator

Intarnadlata

frequency

amplifier

Figure 11. Laser Beam Attenuation Measuring Circuit by Serial Type

Intermediate Frequency Substitution Method

2. Experiments: Experiments were made using an He-Ne laser (5 mW, 633 nm)

with AOM driven at 30 MHz. An ND filter (transmission factor, 0.1) was used

for the photo attenuator and PIN diode with an impedance transducer added to

it was utilized for the photo detector. To know a dynamic range of the

measuring device, measurement was made using the same attenuator (about 1.00

for various laser level inputs. Figure 12 shows the results of experiments on

the serial and the parallel method. In the serial method, lasers at low

levels were susceptible to the influence of noises, resulting in a range of

about 50 dB for the deviation of ±0.15 dB. In the parallel method, the range

was expanded to about 70 dB.

Serial type internediate

X IFrequenoy substitution

_ .nichod

° • Parallel type internediat

Frequency substitution

method

X

-20 -30 -40 -50 -60 -70 -80

Photo attenuator input power (dBn)

Figure 12. Linearity of Intermediate Frequency Substitution Circuit

59
Precision Photo Attenuator

An attenuator capable of comparing theoretical values with measured ones are

advantageous since precision can be confirmed. For this reason, a rotary type

attenuator combining two deflecting plates was adopted to be test

manufactured. To minimize I/) optical axis fluctuations, Grantompson prisms

were used for the deflecting plates. The read resolution for angles of

rotation is 1/40 degree.

10 20

Rttenuation (dB)

30

Figure 13. Difference Between Theoretical and Measured Values of Deflecting

Plate Type Photo Attenuator

Figure 13 shows a difference between the theoretical values and the calculated

ones. The maximum difference is within a range of ±0.07 dB. Incidentally,

dotted lines show an attenuation error corresponding to a rotation angle read

error of 0.04 degrees.

Cons ideration

In the modulated substitution method, the dynamic range is around 50 dB,

limited by nonlinearity in high levels and by noises in low levels. The

method is free from the influence of turbulence on the plane of polarization

compared with the intermediate frequency substitution method.

In the intermediate frequency substitution method, as to ranges with good

linearity and usable for measurement, 50 dB and 70 dB were obtained by the

serial type and parallel type, respectively. A nonlinearity trend is not

found in higher beam levels graphically, greater measuring ranges expected by

increasing laser power. Utilizing beam interference, this method is directly

affected by deflection and turbulence in mode caused by the photo attenuator

with the result that ND filters with ranges of over 20 dB which were used for

experiments resulted in extremely aggravated repeatability. As for a photo

attenuator, a high precision one with a range of about 0.078 dB for 0-30 dB

was obtained.

60
Conclusion

With regard to sensor technologies, a gas molecule sensor using a low-loss

hollow fiber was initially planned. The project attached importance to the

development of a hollow fiber as it is a core technology for that. As stated

before, a principle, so far unavailable for optical fibers, was introduced

into a hollow fiber--use of materials with a reflective index smaller than 1

(or such wavelength areas). As a result, in the infrared area, transmission

efficiency of 2 dB/m was obtained, which is one digit inferior to the

theoretical value and other types of infrared optical fibers (KRS-5, for

example), leaving room for further improvement.

On the other hand, with a soft X-ray transmission optical fiber as well,

transmission characteristic was one digit inferior to the expected value, but

it was the first achievement in the world as an X-ray transmission fiber.

As sensor technologies using a hollow fiber, a gas sensor is considered

significant. Since a great number of gas molecules individually show

characteristic absorption spectrum in the infrared area (10 ym band), a

microquantity of specific gas molecules can be detected by forcing gas into a

long hollow fiber and by scanning it with a laser beam.

An X-ray fiber is not only effective as a sensor technology but expected to

trigger social demand more than that. In medical use, for example, it is easy

to imagine that it will be used with its transmitting distance within several

meters and bending angle within 90 degrees. In this case, its utility value

will be great, if its efficiency is 1 percent, as unnecessary irradiation into

human bodies could be avoided or irradiation of X-rays for medical treatment

could be made for affected parts from the shortest distance.

As for micropower measuring technologies, developments were made of two types

of photo attenuation (power ratio) measuring methods utilizing characteristics

of an acousto-optic modulator and of a precision photo attenuator. The

development of the modulated power substitution method is historic in that

unlike the substitution method conventionally used with microwaves, etc.,

linearity of modulation characteristic was utilized instead of that of wave

detection characteristic. This method permitted a dynamic range of about 50

dB to be obtained, while the intermediate frequency substitution method

utilizing optical interference provided that of 70 dB. The former features

are less susceptible to the influence of optical plane of polarization, etc.

As to the photo attenuator, a high-precision one with a range of 0.07 dB for

30 dB was obtained. Measurement of 10 ym can be made With an accuracy of

about 1 percent at the present phase, so that this technology thus developed

will provide the possibility of measuring 10 nW with an accuracy of several

percent. Meanwhile, a laser beam transmission quantity measuring method using

an acousto-optic modulator was also developed. These measuring methods and

photo attenuators can be expected to find their applications in

instrumentation in other photo sectors.

61
BIBLIOGRAPHY

1. Hidaka, T., Morikawa, T., and Shimada, J., SHINGAKURON, J64-C, No 9,

pp 590-596.

2. Ibid., APPL. PHYS., Vol 152 No 7, pp 4467-4471.

3. Hidaka, T., Kumada, K., Morikawa, T., and Shimada, J., SHINGAKURON,

J65-C, No 9, pp 689-696.

4. Ibid., J. APPL. PHYS., Vol 53 No 8, pp 5484-5490.

5. T. Hidaka, Ibid., Vol 53 No 1, pp 93-97.

6. Ibid., OPT. COMMUNS., Vol 44 No 2, pp 90-93.

7. Hidaka, T., SHINGAKURON, J66-C, No 2, pp 153-154.

8. Watanabe, M., Hidaka, T., Tanino, T., Hoh, K., and Mitsuhashi, Y., APPL.

PHYS. LETT., Vol 45 No 7, pp 725-727.

9. Watanabe, M., Suzuki, I.,Hidaka, T., Nishi, M., and Mitsuhashi, Y., APPL.

OPTICS, Vol 24 No 23, pp 4206-4209.

10. Kawakami, T. and Yokoshima, I., "Laserbeam Attenuation Measurement Using

Acousto-Optic Modulator," ELECTRON. LETT., Vol 19 No 17, 1983, p 653.

11. Kawakami T. and Yokoshima, I., "Large Attenuation Measurement for Laser

Beam by Intermediate Frequency Substitution Method," IEEE TRANS. ON IM,

Vol IM-32 No 3, 1983.

12. Kawakami and Yokojima, "Laser Beam Power Ratio Measurement Using

Acousto-Optic Modulator," Electricity Society's joint seminar on instrumentation, etc., IM-83-35, 1983.

13. Kawakami, Yokojima, and Nawa, "Attention Characteristic of Two

Deflecting Plate Type Laser Attenuator," National General Convention of

Electronics and Communications Society, 840, 1986.

14. Inoue, T., Yokoshima, I., and Hiraide, A., "High Sensitive Calorimeter

for Microwatt Level Laser Power Measurement," CPEM, 1986.

15. Kawakami and Yokojima, "Laser Beam Transmission Quantity Measurement by

1-KHz SSB Homodine Wave Detection Using Acousto-Optic Modulator,"

National General Convention of Electronics and Communications Society,

1985, p 1046.

20117/9365

CSO: 4306/7534

62
LASERS, SENSORS, OPTICS

LASER DEVELOPMENT, EVOLUTION OF APPLIED TECHNOLOGIES DESCRIBED

Tokyo OPTRONICS in Japanese Jan 87 pp 86-91

[Article by Takuzo Sato, head of the Laser Research Office, Electric Wave and

Electronic Department, Electrotechnical laboratory]

[Excerpts] Technologies for Greater Output

Excimer Laser

The history of the excimer laser begins in 1970 when Basov and his colleagues

of the Soviet Union succeeded in laser oscillation in the vacuum ultraviolet

area by irradiating and exciting liquid xenon with electron beams (Table 1).

The research was initially targeted at rare gas excimer or rare gas-oxygen

excimer with low efficiency and capable of oscillating only by electron beams,

but later was pushed forward to the development of a new short wavelength

laser rather than a practical laser. The development of the rare gas halide

excimer laser in 1975, however, has changed the world's understanding of the

excimer laser.

Laser oscillation by the rare gas halide excimer by stimulating electron beams

was confirmed in 1975, followed by successful laser oscillation by the

discharge excitation method in the following year. With regard to the

discharge excitation are gas halide excimer laser, progress has been made in

the research of practical technologies for greater repeatability, greater

power and longer life; lasers with repetition of 500 Hz and the average output

of 100 W are marketed at present and thus have greatly contributed to the

progress of basic research into the semiconductor process and medical sector

as a short wavelength ultraviolet laser for the photochemical process. With

the discharge excitation excimer laser, as stated so far, in addition to

research and development (R&D) of greater repeatability, greater power and

longer life, research is also underway into high efficiency, and long pulses

of the laser, its applicability expected to be greater than ever.

On the other hand, with regard to the electron beam excitation method to

excite directly a laser gas with electron beams, a KrF excimer laser with

great volume (1x1x2 nr) and great power (10.5 kJ, pulse width of 500 ns)

has been developed in the United States for use in research into laser nuclearfusion. The discharge excitation method also has attained X-ray auxiliary

ionization types, one with a caliber of 10 x 8 cm

2

and output of 44 J (85 ns),

and the one with a caliber of 20 x 15 cm

2

and output of 66 J (180 ns).

63
Table 1. Developmental Chronology of Main Excimer Lasers

Exciner laser

Osoilla- tion

waue— length

<nn)

Excitation

nethod

Vear of

osoillation

Rare gas

exoiner

liq-Xe 176 e 1970

Xe2 172 e 1972

Kr* 146 e 1973

Ar2 126 e 1974

Rare gasoxygen exciner

XeO 538, 546 e 1974

KrO 558 e 1974

ArO 558 e 1976

Mercury

halide

exoiner

HKBr 502 e. d. 1 1977

HgCI 558 e, d 1977

HRI •143 e, d 1978

Rare gas

halide

exoiner

KrF 248

e

1975

e . c .

d 1976

XeCl 308

e 1975

d 1977

m 1981

XeBr 282 e 1975

d 1978

XeF 351, 353

e 1975

d 1976

P 1979

ArF 193 e, d 1976

KrCl 222

e 1976

d 1977

ArCI 175 d 1977

XeF

(C A)

483 1 . e. d 1979

Xe*CI 518 e 1980

KraF 430 0 1980

Electron beam excitation

Discharge excitation

Photo excitation

Microwave excitation

p: Proton beam excitation

ec: Electron beam control:

A(*) mark is omitted as, for example,

where excimer KrF*-*KrF.

Free Electron laser

While efforts are being made to provide greater power of the excimer laser in

the ultraviolet area, the research into great power by the free electron laser

in the infrared area is drawing attention. The free electron laser, which

makes use of braking radiation light produced when the transmit direction of a

high-speed free electron (an electron free from atoms or molecules) is bent by

64
a magnetic field, was proposed in 1971, and its laser oscillation first

succeeded in 1977. Its developmental state is shown in Table 2 [omitted].

With regard to the Compton type free electron laser using high-energy smallcurrent electron beam sources (linear accelerator, electron accumulation ring,

van de Graff, etc.), research into laser oscillation from the visible to the

near infrared areas is underway. In a study of the free electron laser using

an electron accumulation ring, success has been achieved in its oscillation in

the visible area (0.85 ym, 0.65 ym) (South Paris University).

A study is being made of the oscillation Raman-type free electron laser using

low-energy great-current electron beam sources from the far infrared to the

millimeter wave areas with a result that a laser providing a great average

output of 6 kW in 9-35 ym wavelength bands has been developed.

Solid Laser

Success was achieved in laser oscillation in the first half of the 1960s by

representative solid lasers such as the ruby laser (1960), Nd: glass laser

(1961), semiconductor laser (1962), Nd: YAG laser (1964) and color center

laser (1965). if we call this era the first solid laser boom, for example,

the recent R&D of solid lasers which has been so active could be called a new

solid laser boom, shown in the development of variable wavelength solid lasers

represented by alexandrite, and by research into providing their great output,

the development of a high-efficiency solid laser including Cr^+added

Nd-J+:GSGG, the development of a great-output solid laser, and the development

of a high-efficiency semiconductor laser-excited total solid laser.

Table 3. Characteristics of Main Variable Wavelength Solid lasers

Laser orystal Wave .

fciR?th Action node

Excitation

illuninant Output

Cr^BeAljO,

(Alexandrite)

701-826

701-826

726-802

Pulse

CW

cw

Flash lanp

Hercury

arc lanp

Kr*" laser

lOOWAuera

50W

600mW

Cr3+:BejAWSi03)6

(Enerald) 729-809 cw Kr* laser 320mW

Cr^CdjScjGaA:

(GSGG)

742-842 cw Ar* Kr+

lasers

SOmW

Cr^KZnF, 785-865 cw Kr* laser ffimW

Cr3*: GdiScAbO«

(GSAG)

780

center

cw Kr* laser 90mW

Cr^ZnWO. 980-1,050

1,030 oen

Pulse

terCW

Rhodanine

Kr* laser

TiJ+:AlA 660-986 cw A** laser

Table 3 shows a developmental stage of variable wavelength solid laser using

vibronic transit. The Nd:YAG laser which has attained great output (average

output of 640 W) is followed by a study pushed forward in pursuit of great

output (average output of 105 W) by the alexandrite laser. Besides these

65
solid lasers, results worth watching have been achieved in the studies of high

output (CW output, 4 W; average output, 11 W) to be provided by the phased

array semiconductor laser and the high-output color center laser (NaCl:OH,

1.41-1.81 ym; CW output, 1.25 W).

In the development of the glass laser with great output for use in laser

nuclear fusion, outputs of 8 kJ (500-750 ps) and 18 kJ have been attained by

the second higher harmonics and the third higher harmonics of the glass laser,

respectively.

Infrared Gas Laser

As for CO2 gas lasers with great output for use in laser beam machining, those

with a continuous oscillation output of 20 kw have been developed in the

cross-flow type and the axial-flow type.

In the study of the HF chemical laser, the output of 4.5 kJ (50 ns) has been

obtained at high efficiency (electric efficiency, 226 percent; chemical

efficiency, 18.5 percent).

Technologies of Shortening Wavelengths

In the vacuum ultraviolet (VUV) and the extreme ultraviolet (XUV) areas,

studies are energetically under way to produce coherent light using nonlinear

optical effects such as the production of higher harmonics and photomixing,

and XUV and the soft X-ray lasers aimed at the X-ray laser (Figure 1).

10»

10«-

I04-

3

0.

0

T

NFM ' Frequency nixing

ASRL'. Anti-Stokes Ranan laser

ASRS: ftnti

xn '. nth higher harnonics

Stokes Ranan scattering

ArF-pumped H2/

Ar2/

ArF- •/

«2 pumped'

" Kr 3

YAGx3 -

ArF KrF XeCI .

'S < < < * _

I?) ?t flASRLVg

(ADP)

07-BaB2O4)

ASRS

ASRL

Y»+ Se,24+

Mo*

C

s

J.

10 20 50 100

Figure 1.

200 Uave- (nm)

length

Main Lasers in UV-XUV Areas and State of Coherent Light Production

by Wavelength Conversion

66
While in the XUV area (10-100 nm), coherent light has been produced only on a

sporadic basis in terms of its wavelengths, but in the VUV area (100-200 nm),

high output variable wavelength coherent light with the output of a kw level

has been obtained in the area ranging from 110 to 190 nm by two photon

resonance and four light wave mixing with metallic vapor such as Hg or Cd as a

nonlinear medium.

The first laser oscillation in the XUV area was observed in Kr gas which has

undergone excitation and ionization by four photon absorption of high-output

ArF excimer laser beam (193 nm). This is an XUV laser involving transit of

the Kr inner shell, with several oscillation lines observed at a wavelength of

about 93 nm.

In addition, XUV stimulated emission at short wavelengths was observed in a

laser producing plasma by glass lasers and CO2 lasers with great power,

thereby resulting in active discussions about the potential of the X-ray

laser. In a laser producing plasma by the CO2 laser, 18.2 nm stimulated

emission light was observed in transit of C ions while in a laser producing

plasma by the second higher harmonics of the glass laser, stimulated emission

light with wavelengths of 20.6 nm and 20.9 nm, 15.5 nm and 10.5 nm was

9ZL+ 9Q+ 4-^9 observed in transit of Se^H

, Y*7and Mo , respectively. Based on these

basic studies, the research into shortened wavelengths is expected to be

pushed toward the X-ray laser in the future.

Technologies of Extremely Shortening Pulses

Since success in 1974 in producing extremely short pulses of below a

picosecond by the passive mode synchronizing method with continuous

oscillation dye lasers, followed in 1981 by producing ultrashort pulse of

90 fs by the colliding pulse mode synchronizing method (CPM), the research

into femtosecond pulse laser technology has been made active (Figure 2).

In addition, the ultrashort pulse obtained by the PCM can be further shortened

by the pulse compression system consisting of optical fibers and paired

diffraction gratings. An ultrashort femtosecond pulse of 8 fs had been

achieved by making an ultrashort pulse of 40 fs obtained from the CPM dye

laser with its amplification system go through the pulse compression system.

Ultrashort pulses like this will provide an effective means for research into

ultrahigh speed phenomena such as the relaxation process between solid

excitation levels and the reaction process of biomolecules.

Developmental State of Commercial Lasers

As R&D improves technologies for greater output, shorter wavelengths and

shorter pulses of lasers, the performance of market products using state-ofthe-art technology has improved and new products have appeared in succession.

Since it is impossible to describe the developmental trend of all of these

commercial lasers, Table 4 shows only special items of major new lasers on the

market.

67
1-12

B

C

0

0

01u

£

I»

U

ID

H

3

0.

8

4

2

IO-"

8h

6

4 -

2-

10,-w

81-

6

4|-

10"

Linear- resonator type

Mode synchronization CU

Dye laser

CPM laser

i

Optioal pulse

conpress ion

I ps

100 fs

lOfs

1970 1975 1980

(Vear)

1985 1990 I fs

Figure 2. Trends of Ultrashort Pulse Production

Evolution of Laser Applied Technologies

The number of lasers sold in the noncomraunist sphere in 1985 reportedly

accounted for about 2.84 million semiconductor lasers, about 200,000 He-Ne

lasers, about 11,300 ion lasers, about 4,800 solid lasers, about 2,900 C02

lasers, about 1,500 He-Cd lasers, about 780 dye lasers and about 360 excimer

lasers. By value, they are as follows: the semiconductor laser, about $107

million; solid laser, about $106 million; CO2 laser, about $101 million, ion

laser, about $77 million; He-Ne laser, about $44 million; dye laser, about $25

million; excimer laser, about $17 million, and He-Cd laser, about $5 million

(Figure 3).

The laser gross production 1985 (about $482 million) shows a 23 percent

increase over the year ago level, and this stems from an increase in demand

for semiconductor lasers in Japan. The production of semiconductor lasers in

1985 shows an increase of about 190 percent over the previous year, which is

why 1985 is referred to as the year of the semiconductor laser. The

production in 1985 of 789-nm semiconductor lasers for compact disks in

particular increased to 2.7 million compared to 870,000 in 1984. The

production for laser printers increased from 20,000 in 1984 to 200,000 in

1985, a further increase to 650,000 is estimated for 1986. Sixty percent of

68
Table 4. Developmental Stage of Commercial Lasers

Laser

Output Life

mW h

(1981-1982")

Reoent speoial itens op

connercial laser

(1985-1986)

Sentconductor

1-15

(HOOnm

-1.5|fli)

>10.000

•Shortening wavelengthsi

758nn—Red

•Providing higher output:

Phase array type 2BBnU

(CU, roon tenperature)

Effioienoy >2SX Providing longer life:

->5d.nnpih rr.u. mn„ui

He-Ne

0.5-20

I633nmj

-20,000 .Green He-Ne lasen 543. E nn

Ar- ion

5 MO

Airoooling

-2,000 .Providingi longer liFe:

18,88Bh

He-Cd

5-40

(I42nm)

5,000

•Providing higher output:

lEnU (32E nn)

188nW (442 nn)

Exciner

20W

(200Hz>

10'shot

•Providing high repeatability

great output: 188W(5BBHz)

.Providing longer life:

IB-? shot (XeCl. KrF)

Nd: YAG

.Providing greater output:

488U(average output)288U/CU

CU seoond higher harnonics

(532nn, 2U)

•Senioonduotor laser excited:

NdlYAQ laser

70nU (1.864 un. CU)

18nU (532 nn, CU)

Uariibli

wavelength

solid laser

• Alexandrite

i'730~?80nm)

•Cr:GSGGl745-835nm)

Cr: KZnFii780-850nmi

Dye

•Exoiner

laser exoited

dye laser

.Providing ultrashort pulses:

2SBfc passive node synchronization

' CU infrared dye laser

COt

.Hinlaturization: Mixing of

lasers with robotios

.Autonation of control

Metallic

vapor

.Bold vapor, copper vapor:

Air cooling, 18U

I628nm) !510,578nm)

the gross product of semiconductor lasers is related to optical communications

while 20 percent concerns optical memories (audio disks, video disks, computer

memories, etc.).

The gross product ($6.378 billion) of laser applied systems in 1985 shows a

growth rate of 47 percent over the previous year. This stems from the growth

of semiconductor laser applied systems (optical fiber communication systems,

$1.5 billion; laser printer systems $1.8 billion; and audio disk systems $600

million) (Figure 4). [Figures as published]

69
600

Itfc

H 500

H

H

0

TJ

4. 400

0

It

0 300

•M

H

H

•M

E 200

100

(Forecast)

1

1

1

1

t

1

1

1

f

/

/

/

*

/

1

h

t/>

'/

/

Solid

-

///

//

/

/

/

/

/

' i

1/

//;

/

*

*

Ion

—He-Ne

—He-Cd

— Exciner

Dyt

—Senicondi

CO,

(Laser)

1984 1985 1986

Figure 3. Production Scales of Various Lasers

(in the noncommunist area)

10,000

u

c.

«

H

H

0

0

Ik

0

It

c

0

•M

H

H

8,000 -

6,000

4,000

2,000

/lange Finder, etc.

D^Ciuil engineering,

and construction

Bar code scanner

Color separator

Inspection, instrunentation

Video disk,

nenory

Audio disk

printer

Optical communications

Figure 4. Production Scales of Laser Applied Systems

(in the noncommunist area)

70
The CO2 and the solid lasers, with a product equal to that of the

semiconductor laser, are used mainly for laser machining and medical

applications such as a laser surgical knife. The output of CO2 lasers for

laser machining and medical treatment accounted for 1,200 units (1985) and

1,100 units, respectively, while, by product value, 70 and 15 percent are for

laser machining and medical treatment, respectively. Meanwhile, the output of

solid lasers for laser machining and medical treatment accounted for 900 units

and 650 units, respectively, while the product value for laser machining is a

little below 14 percent and that for medical treatment is almost the same, a

little below 15 percent. The Nd:YAG laser is, of course, the most important

of solid lasers, about 50 percent of the value (output of 2,500 units) of the

output of which is for military use such as a range finder.

Close to 40 percent of the ion laser output is used for medical treatment with

about 15 percent for color separators. In the medical sector, it is in demand

for treatment in ophthalmology and for diagnosis of cell separation, etc. The

ion laser excited dye laser has been used for treatment because it permits

free choice of wavelengths suitable for the absorption of ocular tissues. The

dye laser is mainly used in basic research sectors, and good results have been

achieved in studies of the production and instrumentation of femtosecond

ultrashort pulses, cell separation and photochemical treatment of cancers.

While 40 percent of the He-Ne laser output is used for laser printers and 20

percent is for bar code scanners, the semiconductor laser has penetrated into

this sector. Thirty-three percent of the He-Cd laser output is related to

laser printers, but the demand has been moderate.

As for the excimer laser, 90 percent of its output is used for R&D as a laser

providing high power in the short wavelength ultraviolet area. Good results

have been achieved in the study of ultramicromachining such as laser CVD,

laser etching and laser doping via the optical excitation process by the

excimer laser plus the study of photochemical treatment of vital tissues. The

demand for the micromachining device applying the excimer laser has increased

since about 1984 and test manufacturing of medical treatment equipment began

recently.

Conclusion

In this article, the development of lasers and the trend of applied

technologies have been outlined. Progress in laser technologies has never

stopped during the quarter of a century since its invention and we do not know

where it will stop. New laser technologies have been developed in succession

and they are in turn inducing new applied technologies. Demand for the room

temperature CW oscillation semiconductor laser has, for example, expanded from

optical fiber communications to the applied sector of welfare and industrial

equipment including a laser printer, and, at the same time, it is expected

that new applied sectors such as the development of the semiconductor laser

excited solid laser, and its application to space airframe loaded laser

applied systems and coherent communications. Also, future progress is to be

noted and expected in new lasers and applied technologies such as new laser

machining technology mixing laser technology with robotics,

ultramicromachining technology and laser isotope separation using the excimer

laser.

71
BIBLIOGRAPHY

1. Sato, "Research Into Lasers," 13, 927, 1985.

2. Ibid., ELECTRONIC COMMUNICATION SOCIETY JOURNAL, 67, 991, 1984.

3. Fisher, C.H., et al., APPL. PHYS. LETT., 48, 1574 (1986).

4. Miyazaki, K., et al., J. APPL. PHYS., 60, 2721 (1986).

5. Hazama, et al., "Research Into Lasers," 14, 108, 1986.

6. LASER FOCUS/ELECTRO-OPTICS, 22, No 5, 8 (1986).

7. Deacon, D.A.G., et al., PHYS. REV. LETT., 38, 892 (1977).

8. Billardon, M., et al., IEEE J. QUANTUM ELECTRON., QE-21, 805 (1985)

9. Brau, CA., Ibid., QE-21, 824 (1985).

10. Walling, J.C., et al., Ibid., QE-21, 1568 (1985).

11. Moulton, P.F., LASER FOCUS 19, No 5, 83 (1983).

12. Sipes, D.L., APPL. PHYS. LETT., 47, 74 (1985).

13. Sato, ELECTRONIC COMMUNICATIONS SOCIETY JOURNAL, 68, 337, 1985.

14. Ishida, et al., CLEO'85 DIGEST, 302 (1985).

15. Imai, et al., Ibid., 106 (1986).

16. Scifres, D., Ibid., 64 (1986).

17. Pinto, J.F., et al., OPT. LETT., 11, 519 (1986).

18. Nishimura, H., et al., CLEO'86 DIGEST, 318 (1986).

19. LASER FOCUS/ELECTRO-OPTICS, 22, No 2, 8 (1986).

20. Tabata, N., et al., CLEO'84 DIGEST, 54 (1986).

21. Kuwabara, K., et al., Ibid., 220 (1986).

22. Kannari, F., et al., APPL. PHYS. LETT., 48, 266 (1986).

23. Miyazaki and Sato, ELECTRICITY SOCIETY JOURNAL, 105, 525, 1985.

24. Hilbig, R., et al., J. QUANTUM ELECTRON., QE-19, 1759 (1983).

25. Miyazaki, K., et al., OPT. LETT., 9, 457 (1984).

72
26. Boyer, K., et al., J. OPT. SOC. AM., Bl, 3 (1984).

27. Milchberg, H., et al., APPL. PHYS. ELTT., 47, 1151 (1985).

28. Matthews, D.L., et al., PHYS. REV. LETT., 54, 110 (1985).

29. LASER FOCUS/ELECTRO-OPTICS, 22, No 3, 12 91986).

30. Fork, R.L., et al., APPL. PHYS. LETT., 38, 671 (1981).

31. Yamashita and Sato, APPLIED PHYSICS, 55, 306, 1986.

32. Knox, W.H., et al., APPL. PHYS. LETT., 46, 1120 (1985).

33. Holmes, L., LASER FOCUS/ELECTRO-OPTICS, 22, No 1, 100 (1986)

34. LASERS & APPLICATIONS, 5, No 1, 45 (1986).

20117/9365

CSO: 4306/2503

73
TELECOMMUNICATIONS

STATUS, OUTLOOK OF OPTICAL TECHNOLOGY IN INFORMATION EQUIPMENT FIELD

Tokyo OPTRONICS in Japanese Mar 87 pp 65-73

[Excerpts] 1. "Optical Industry" Achieves More Than a 10-Fold Growth in 10

Years

The highly touted electronics industry, expected to be the trigger industry of

the 1980s, suddenly lost steam in the latter half of the 1980s; in 1986 it

stood at only 99.8 percent of the year before, suffering a minus growth for

the first time in 11 years.

In this situation, only optoelectronics has been experiencing a boom in

business.

Optoelectronics in the past was considered merely a part of electronics, but

the founding of the Optoelectronic Industry and Technology Development

Association (OITDA), which has been engaged in the gathering of data on its

own and been making public since 1982 the results of the information thus

collected, has elevated optoelectronics to the status of "optoelectronic

industry. The optoelectronic industry has achieved a remarkable growth in the

past 4 years, and as is shown in Table 1, it has now grown into a trillion yen

industry.

The growth rate up till 1986 registered a high "year-ago" level, achieving a

167 percent gain over the preceding year in 1983, similarly a 138 percent gain

in 1984, a 135 percent gain in 1985 and a 123 percent gain in 1986. Up until

1985, electronics as a whole had continued to enjoy two-digit growth over the

previous year, attaining a 117 percent increase over the preceding year in

1983, a 129 percent increase in 1984 and a 110 percent increase in 1985; but

in 1986 the industry suffered a negative growth of 0.2 percent compared to

1985. The setback naturally had a negative effect on the optoelectronic

industry division, so a letdown in its 1986 growth rate in comparison with the

figure for 1985 could hardly be avoided. Given the situation, the 123 percent

growth rate can be called very strong.

The differences in the growth rate between the electronics industry and the

optoelectronics industry are attributable to the following factor: while the

former contains such merchandise as conventional color TVs, conventional audio

equipment, VTRs and single work robots which are entering the maturity period

in their life cycle, the latter is almost all made up of products which are at

the beginning period growth period.

74
Table 1. Scale of Production of Optoelectronic Industry

(Unit: Yl million)

Product nanes IttoffVBroduccoros

Projected FV 8( production

Optical parts

Light-emitting elements 134.719 159.293

Seniconductor lasers 40,797 54.015

8,887 Gaseous lasers 8,027

Solid lasers 3,635 2.935

Light-emitting diodes 82,198 93.386

(For communications) ( 5,075) (16.034)

(not For connunications) (77,123) (77,352)

Other lasers 62 70

Light-receiving elenents (such as

discrete 23.946 light-receiving elenents) 29.325

Compound optical elenents 32.463 39,186

Solar cells 10.565 12.002

Optical Fibers (including cable) 54.059 67,228

Quartz Fiber 51.771 64.665 Non-quartz Fibers (plastic.

light guides, etc.) 2.288 2.563

Other optical parts 46.371 62,449

Connectors/plugs 6.933 8.974

Optical circuit parts/others 39,438 53,475

Subtotal 302,123 369,483

Optical devioes/equipnent

Optical transnission devices/ 28,234 36.456

Optical measuring instrunents 20,717 26.753

Fibei—laying equipment 5,024 4,707

Dptical Fiber sensors 2,501 4,502

Laser-based sensors 6.894 8.864

Optical type disks 249,653 300,075

Digital audio disk service 198.252 236,861

Video disk devices 45.783 50,279

Rdditional storage disks

(documents, data Files) 5.130 12,030

Recording nedia (For CD-RDM,

additional recording) 488 905

Optical input/output devices 75,943 102.440

Medical laser equipment 4.833 5.829

Laser nachining equipment/others 52.878 53.570

Subtotal 446,677 543.196

Optics-applied systems

Optical conmunications systens 92.662 119.662

Public conmunications systens 53.154 65,627

Leased conmunications systems 39.508 54,035

Others 6.434 7,226

Subtotal 99.096 126,888

Brand total 847.896 1 ,039,567

Prior to making public forecasts for the amounts of production of

optoelectronics in 1986, OITDA came out with estimates on quantitative

increases in the output of optoelectronics up to the year 1990, which are

tabulated in Table 2. It shows how great an expectation people are placing on

the optoelectronic industry. Putting aside the issue of farsightedness of the

forecasts, the optoelectronic industry, which was in a scale of Y83 billion in

1980, will have grown at more than double the growth rate for the entire

electronics industry.

75
Table 2. Current and Projected Future Demands for Optical Products

Optical Parts

Optical products Unit 1985 1990

Average annual

growth rate

(percent)

Semiconductor laser

1985-199B

Long wavelength band (1.55-un band ipieci M*l 1.000

Long wavelength band (1.3B-un band ) » 15.000 200.000 70

Short wavelength band(B.B5-un banc ) ' 15.000 108.000 48

Visible area (B.7B-pn band) tt 3.500.000 34,000.000 58

Gaseous lasers

He-He laser

set

150.000 180.000 4

Argon laser it 2,600 6.000 18

Co 2 laser n 700 2.500 29

Exciner laser ii HO 1,300 56

Solid lasers

Ruby laser

Glass laser

set

n

15

30

15

30

0

0

VAG laser II 900 3,500 31

Dye laser II 100 640 45

Light-enitting diodes

LED For discrete display

LED For nunber/letter display

LED For connunications

(1.30-un band) LED For connunications

piece

u

H

II

1,600.000.000

90.000.000

10.000

120.000

5,000,000.000

350.000.000

730.000

1.200.000

26

31

136

58

(B.B5-un band)

Optical Fibers

Quartz nultinode Si Fiber b-co •e 6.700 30,000 35

Quartz nultinode Ci Fiber H 35.000 800.000 87

Quartz single node Fiber

» 82.000 250.000 25

tlulticonponent nultinode Si

Fiber f 4.000 13.000 27

Light-related parts

Light branching/binding device piece 3.500 58.000 75

Light wave branching/binding

device

Light attenuator

3,700

16.000

920.000

225.000

201

70

Isolator » 600 15.000 90

Optical switch ir 7.500 730.000 150

Optical connector » 1.900,000 25.000.000 67

[continued]

There is, of course, no guarantee that the optoelectronic industry will keep

on growing at that pace for the next five years, but it would not be too farfetched if one thought the industry would achieve more than a 10-fold growth

in the coming 10 years.

76
[Continuation of Table 2]

Optical Instrunents/Equipnent

Average annual

Optical products Unit 1985 1990 growth rate

(percent)

lvBS-1990 Optical transnission devices/equipnent

Digital optical transnission devices, '

equipnent

Sinple type Clinks) set 600,000 3.200.000 40

Ordinary optical transnission unit 3.500 110.000 99

equipnent

Analog optical transnission devices/

equipnent _

Sinple type

Ordinary optical transnission equii

set 8.(00

220

86.000

7.000

58

100

Optical noden II 3.000 17.000 41

Spatial propagation equipnent H 430 63.000 171

Measuring devices For optical

transnissions unit 1.800 7.400 33 Standard power source

Power neter

)r 8.400 35.000 33

Measuring equipnent oF optical

transnission Features

Baseband transnission characteristics neasuring devices unit 50 700 70

Wavelength dispersion neasuring u netf 170 devices

Light loss neasuring devices ' ' 500 2,000 34

Obstacle position detector (DTDR) 330 1,400 34

Wavelength neter 460 1.700 30

Optical sensors (sensors using lasers

or Fibers)

Tenperature sensor unit 200 50.000 202

Others u 760 9,700 66

Optical disk player

Reproduction-only video disk unit 200.000 1,000.000 38

Additional urite-in optical disk w 1.300 17.000 67

Rewritable optical disk w 0 2,000

Rewritable conpact disk h 900,000 8,000.000 55

Optical type printers

Seniconductor laser printer unit 20,000 640.000 100

Gaseous laser printer it 1.800 4,700 21

LED printer " 800 60.000 137

Liquid crystal printer if 350 120,000 221

Laser scanner 5.500 22.500 33

Medical laser equipnent unit 280 710 20

Laser applied production equipnent

YAG laser tf. 535 2.785 39

CO 2 gas laser » 295 2,280 51

2. Three "Hardware Technologies" for Realizing an Information Society

The society is oriented toward an information society. In an information

society, a service provision system must be in place, in which, by solving the

contradictions between the time series and the amount of information existing

in the conventional means of data transmission, user demands for various

77
information can be met on a timely basis. The type of information service

that will contribute greatly to an individual or a corporate decision-making

but that is either unobtainable or too expensive to obtain with conventional

means in terms of hardware or software can be obtained at a reasonable cost.

The user would come to think it profitable to pay a price for the service

provided, and an opportunity for starting a business would emerge.

For a service system as such to emerge, as things stand now, even the hardware

technology, to say nothing of software technology, is scarcely satisfactory,

and its development is awaited.

The necessary hardware technology can be summed up as follows: (1) technology

for processing a large amount of data, (2) technology for stockpiling a large

volume of data, and (3) technology for transmitting a large volume of data.

2.1 Massive data processing technology

Suppose you are a researcher and are looking for domestic and foreign

literature on plant genetic engineering. With the conventional method, you

would have to call on experts in the field or would have to browse through

domestic or foreign academic journals. Even then, the available data may be

limited. The time and labor needed for the checkup would be considerable.

If, as is the case with the on-line database service, data could be checked in

minutes or copies of it could be printed to within a few hours by merely

typing necessary words into the keyboard following the guidebook, research

efficiency would be greatly enhanced.

But if such a software service were available, an appropriate amount of

hardware corresponding to the service requirements would have to be utilized.

The first is that the data base center must be stockpiled with writing, with

the papers indexed. On the part of the data base center, if the literature is

to be speedily input, the conventional method of inputting in which an

operator types words into the keyboard would require too many manhours. In

other words, existing von Neumann computers are not provided with interface

that can understand the natural language. Therefore, a machine with a large

data processing capability is needed that will be able to scan the literature

and turn the contents into electrical signals for storage. The non-von

Neumann computer being developed by the Institute for New Generation Computer

Technology (ICOT), the optical computer expected to be provided with the

capability to recognize patterns easily, and AI (artificial intelligence) that

will enable it to pick up appropriate answers from a large volume of data, for

example, will fall into the category of such machines.

2.2 Massive Information Stocking Technology

Next comes a need for a storage device that can keep in stock economically a

large volume of data. Conventionally, this role has been played by magnetic

tape and magnetic disk. But, as the volume of data increased, if magnetic

memories with a low surface recording density (storage capacity per unit area;

the number of bits that can be stored in an area of 1 cm

2

) were to be used,

the storage system would have to be of an enormous scale, and this would also

result in a slower retrieval time. Here arises the need for the development

78
of large capacity filing systems like optical disk, optical magnetic disk and

photochemical hole burning memory.

As a new audiovisual system that is expected to bring into reality the day of

home theater, VD (video disk) is emerging rapidly. VD comes in optical and

electrostatic types, and this is another area where optical technology is

being made the most of. Differing from a CD that can record only voice, a VD

can record a large volume of images. So, in it, recording is made not in

digital signals but in frequency modulated analog signals, and a 0.63-micron

HeNe gas laser is used for high-density recording.

If a laser diode with a wavelength on the order of 0.6 micron is developed, it

will substitute for a HeNe laser, and this will open the way for a VD=CD

compatible disk (temporary designation). In fact, Pioneer Electronic

Corporation has already commercialized a such a device.

As the optical disk is called by another name of CD-ROM, it is not amenable to

rewriting. So, the additional entry type of optical disk which has a margin

of blank space is becoming the mainstay. But if optical disks are to

substitute for magnetic disks completely, they will have to be amenable to

rewriting.

Two systems are proposed for rewritable optical disk. One developed by ECD of

the United States takes advantage of phase changes from crystalline to

amorphous and vice versa in low tellurium oxide (TeO) and others, and efforts

are being made to make commercial use of the introduced technology but no

product has yet to be commercialized because of alterations in the recording

with passage of time.

The other is the photoelectromagnetic disk developed by Kokusai Denshin Denwa

Co (KDD) and Nihon Hoso Kyokai (NHK) that utilizes the magnetic Kerr effect in

amorphous-Tb-Fe-Co alloys. Hitachi (12-inch diameter) and Sony (30-inch

diameter) had developed prototypes as early as autumn 1985, and generalpurpose 5.25-inch types are expected to be commercialized within one year.

Since the photoelectromagnetic disk has a recording density as high as the

optical disk and, moreover, since it has a rewrite capability as high as the

magnetic disk, it has the potential to replace magnetic hard disks entirely.

In connection with the disk, development of an LD with an overwrite

capability, a capacity to simultaneously perform erasion and write functions,

is being targeted.

The need for increased recording density is limitless. So, despite the

technical barrier of how to set the access time, development of a short

wavelength LD combined with SHG (second harmonic generation) is taking on the

shape of a concrete theme. Studies are also being made for the introduction

of the short wavelength and high energy excimer laser, wavelength variable

lasers utilizing new solid lasers like alexandrite (BeA^O^), and free

electron lasers, and practical use of photochemical hole burning memories as

the next-generation device is no longer a mere dream.

79
2.3 Massive Information Transmission Technology

Next, in the relationship between information provider and information user, a

system will be needed that can transmit a large volume of information speedily

in both directions. Existing data networks are satisfying the requirement to

some extent, but under the existing telecommunications systems even the TV

telephone is far from the stage of widespread use. In an information society

the volume of information that includes not only numbers and letters but also

graphics and images is greater by several orders of magnitude. Hence, there

will arise a need for nationwide networks of optical fiber communications

which are more suited for mass transmission of data than the

telecommunications system, and such a need will also arise in the case of

international transmissions. The wavelength multiplexed coherent optical

communications and the transpacific submarine optical cable should comply with

such needs.

Optoelectronic technology is expected to play a very great role in

establishing the aforementioned three "hardware technologies."

3. Optoelectronic technology finds wide use in the data processing equipment

field

3.1 Light-emitting diode (LED)

CRT and EL are widely employed in displays as light emitting elements, and the

representative light-emitting element for optoelectronics is the compound

semiconductor light-emitting diode, LED (Electro Emitting Diode).

LED is expanding its field of application as visible LED lamps, infrared LED

lamps and LED numerical display elements.

Among the LEDs most widely used are the red color light gallium phosphide

(GaP), gallium-arsenide-phosphide (GaAsP), and gallium-aluminum-arsenide

(GaAlAs), and their peak wavelength is from 0.63 to 0.7 micron.

As for the luminance of LEDs being put to practical use, thanks to their

double hetero layer, all have achieved a luminance ranging from 500

millicandelas to 1,000 millicandelas, and some are about to realize a

luminance of several thousand millicandelas.

LED of blue color, the last of the three basic colors, is in the development

stage. Matsushita Electronics Corp is developing a blue LED of a MIS (metal

insulator semiconductor) structure that is formed by mounting gallium and

nitrogen on a sapphire substrate. The three-member consortium of Kyoto

University, Osaka University, and the Government Industrial Research

Institute, Osaka, of the Agency of Industrial Science and Technology, along

with Toshiba Corp, are separately engaged in the development of a blue LED of

a MIS structure that is formed by fabricating the N layer of zinc sulfide

(ZnS) crystal and an insulating layer by means of the MOCVD (metal oxide

chemical vapor deposition) method and adding to the monolithic electrode

metals. Furthermore, development of a blue LED based on silicon carbide (SiC)

is underway. Compared with LEDs of other colors, blue LEDs have luminance

80
levels that are smaller by two to three orders of magnitude, so the key is how

to raise their luminance.

The current market for LEDs is only at the scale of Y93.4 billion, but the LED

panel and optical communications light-emitting element markets should grow at

an annual rate of 10 percent, pushing the total sales to a level of Y200

billion by 1990.

3.2 Laser diode (LD)

An LD is also a compound semiconductor light-emitting element in which light

stimulated by an external energy and discharged is reflected in large part at

the cleavage plane of a semiconductor single crystal to be returned to the

active layer for a reexcitation, and the discharged light also repeats the

same back and forth movement, gradually increasing its strength to a point

where it wins over the propagation loss when the stimulated emission light is

radiated to the outside.

Such light is called laser; it is a phased light with a fixed wavelength.

Such a light-emitting element is called a laser diode (LD). The advantage of

an LD lies in the fact that since it, although small in output power, utilizes

its own cleavage plane, it does not need any reflecting mirrors, thus enabling

it to be fabricated as an extremely small, compact device.

GaAs-AlxGa;L-xAs semiconductor lasers which are representative IDs have

wavelengths in the 0.78-0.85 micron range, and they are used as the laser

source in fiber optic telecommunications or in DAD (digital audio disk).

Semiconductor Lasers for Optical Telecommunications

In optical communications, the key to repeaterless transmission is the light

loss of optical fiber. Quartz fibers widely used at present have a feature

that they show the minimum light loss at 1.55 microns in wavelength, so the

loss will be great at 0.85 micron. So, development of semiconductor lasers in

the 1.3 microns to 1.5 microns range is being undertaken.

The most promising materials for such lasers are a class of In^a^As]_-„?„

(indium-gallium-arsenide-phosphide) compounds, and they are of a structure in

which InGaAsP-InP-InGaAsP is epitaxially grown on an InP substrate, and

furthermore a buried-in type of products has been developed. The fiber optic

trunk line running along the length of the Japanese archipelago is equipped

with 1.3-micron IDs, a device that enables repeaterless transmission over a

30-kilometer span. Furthermore, a distribution feedback (DFG) type LD has

been trial manufactured by using an InxGa^xAsiL-yPy compound and it has

enabled 300-kilometer repeaterless transmission in an experiment, thus giving

it a star role in the future long distance optical communications.

Ultralong distance transmissions beyond that are, however, beyond the limits

of light loss of quartz optical fibers, so non-quartz optical fibers with a

wavelength in the infrared region are needed. The National Research Institute

for Metals, Science and Technology Agency, has experimentally developed a

PbS/PbCdSSe double heterojunction laser for use as an LD in the 2-3 micron

range.

81
Semiconductor Lasers for Optical Memories

For CDs (DADs), 0.78 micron-band IDs made from GaxAl^-xAs compounds are mainly

used. But for VD (videodisk) optical disks, a shorter wavelength is needed,

and HeNe laser (0.63 micron) and Ar laser (0.5 micron) are employed.

But gas lasers have too many constraints in terms of both space and cost, so

development of short wavelength LDs is awaited.

LDs in the 0.68 micron to 0.69 micron range have experimentally been

manufactured using GaxAl^-xAs compounds for Ir^Ga^-jjASyPi^ compounds, but

they have yet to be put to practical use. On the other hand, attempts have

been made by Matsushita Electric Industrial Co and others to obtain 0.415

micron instead of the 0.83 micron from LD by taking advantage of the secondary

harmonic generation (SHG) of nonlinear optical materials such as LiNbOß

(lithium niobate).

Semiconductor Lasers for Laser Printers

Recently, in competition to conventional gas laser printers, commercialization

of semiconductor laser printers has begun to catch on by taking advantage of

their low cost and compact size, and GaxAl^-xAs materials have come to be used

as the laser oscillators.

Production of semiconductor lasers in 1986 was worth only about Y88.9 billion.

However, with the addition of laser printers in addition to conventional

optical fiber communications, DAD and optical disks in which they are being

applied, production of semiconductor lasers should grow at an average annual

rate of 30 percent, reaching the market level of about Y250 billion by the

year 1990.

3.3 Light-receiving elements (photodiodes)

While a light-emitting element converts an electrical signal into an optical

signal, a light-receiving element has the role of converting a received

optical signal into an electrical signal. In optical communications, both

devices are installed at both ends of transmission.

Different materials are used for light-receiving elements with different uses.

Among the materials with a sensitivity to the 0.85-micron region of GaAs are

Si (silicon), Ge (germanium) and GaAs-AlGaAs, but in practice, Si is widely

used. The material suited for use for the 1-2 microns range of light such as

that of InGaAsP is Ge, but the material has problems in the form of a large

dark current (a current that flows without light radiation) in Ge-APD

(Avalanche Photo Diode), slow response and large noise, so compounds of the

II-V groups are beginning to draw attention. Included among them, for

example, are InxGa^-xAs^-yAs^-jjPy, In^-xGa/xAs. and GaxAl^-ySby.

Among application fields of light-receiving elements are solid imaging tubes

for VTR cameras and visual sensors, in addition to optical communications.

87.
The basic structure of photodiodes widely used in solid imaging tubes and

visual sensors is the same as that of MOS for IC, and it consists of the three

layers of Al metal electrode and Si(>2 and Si single crystals, further provided

with the photodiode in the light-receiving region and CCD that stores and

transfers electric charges. When a beam of light strikes the photodiode

(reflected light), a charge is generated by the action of the photoelectric

transfer effect in proportion to its strength. Up to this point, MOS IC and

CCD are same in their mechanism, but the difference is that the latter stores

and transfers charges.

The market for light-receiving elements at present is worth only about Y29.3

billion a year. This is because, as merchandise, optical fiber

communications, visual robots, VTR cameras and magnetic disk cameras are still

in their early stages of growth; but the demand may increase greatly as the

markets for these products mature.

Growing at an average annual growth rate of 20 percent, the market should

reach the level of Y60 billion by the year 1990.

The market for composite optical elements such as photocouplers and

photointerlamps incorporating photodiodes is at a level of Y39 billion at

present, but it should grow to the level of Y90 billion in keeping with the

growth tempo of photodiodes.

3.4 Fiber optic communications

When the telephone is used as an example, the mechanism of optical fiber

communications is explained as follows: first, voice is transformed into an

electric current.

Next, the current is converted by a light-emitting device (LD) into laser.

The laser light is transmitted via a quartz fiber to a light-receiving device

(photodiode) at the receiving side where it is converted back into a current.

The current is further converted into a voice to reach the human year.

Light-emitting device

Voice--current--laser--optical fiber--laser--current--voice

Light-receiving device

Quartz glass fiber of two-layered structure provided with a core of a high

refractive index and a clad of a low refractive index is widely used for the

optical fibers. With an external diameter of 125 microns, the single-mode

fiber has an inside diameter of 10 microns and the multi-mode fiber has an

inside diameter of 50 microns.

83
Besides the above, among optical fibers are included the multi-element glass

fiber containing such elements as silicon dioxide, alumina and sodium oxide,

and the methyl methacrylate plastic fiber.

Compared with quartz fibers, these fibers are low in cost, so they are

appropriate for such short-haul applications as office automation, control

cables in plants, or automobiles. Compared with quartz fibers, they,

however, have a large light loss, so quartz fibers are still the mainstay.

NTT, the world leader in technology, completed in January 1985 a 3,400-km

optical fiber trunk line system running along the length of the Japanese

archipelago from Asahikawa to Kagoshima, and it has a transmission capacity of

400 Mbit/sec. The 1.3-micron LDs in the system are to be replaced by

1.55-micron DFB-LDs by 1988, and the capacity should be increased to

1.6 Gbit/sec. And it is almost certain that by the first half of the 1990s,

the majority of the domestic trunk lines and links between stations will be

connected by optical cables. By the year 2000, almost all domestic

communications will have been switched over to fiber optic communications

links.

The prerequisite for fiber optic communications networks to expand to the

level of the subscriber loop is the practical use of such light-activated

components as isolator-type optical amplifiers, optical switches comprising an

optical switchboard, and optical IC (OEIC). Various ideas have been proposed

by NTT and domestic makers, and these optical devices should reach the stage

of practical application by the early 1990s.

The trends in the development of optical communications in the future will

probably take the form of (1) increased transmission capacity and (2) increase

in the transmission distance without amplification. As for item (1), Toshiba

corp has already succeeded in a five wavelength multiplex transmission

experiment using an optical wave dividing and combining device.

Furthermore, in place of the IM system using "1" and "0" the FSK and PSK

systems called coherent optical communications are being developed.

Next, the key to the realization of transmission over ultralong distances of

several hundred or several thousand kilometers without amplification is the

development of non-quartz optical fibers in the infrared portion of the

spectrum and work is underway for the development of ZrF^ GeS and Tl (Br,I)

fibers and these fibers should reach the levels of practical use by the latter

half of the 1990s.

The market for optical fiber communications in 1986 was still small at about

Y120 billion, but production of optical communications systems in 1995 should

be at the level of Yl trillion at the minimum. Of this, optical fibers and

optical components are expected to account for Y600 billion. Of the Y10

trillion, public communications systems are expected to account for Y700

billion and the specialized user systems like LAN and OA Y300 billion.

[Figures as published]

84
3.5 Storage devices

The debut of LP record albums 30 years ago had dispelled the conventional SP

albums form the market in less than 10 years. A same phenomenon is about to

take place. This time it owes to the debut of DAD (digital audio disk) that

came to the market in the fall of 1982 and CD (compact disk).

A CD is one-third as large as a LP record but is crammed with five times as

much sound. For the purpose, a CD has as many as 5 billion to 67 billion

small bits of 1-micron size pitted on its surface. The small bits are

equivalent to groove amplitudes of LP records. Consequently, CD can reproduce

the original sound with high fidelity.

CD has not only brought about a revolution in the record album industry but is

beginning to start a similar revolution in the field of data stock. The

horizontal magnetic recording density of such peripheral storage devices as

magnetic disks and magnetic tapes found in the computer room is from 300,000

to 400,000 bits per square centimeter (1 cnr), but optical recording systems

have more than 10 million bits for the same size. Consequently, the adoption

of a recording system based on optical disks could do the job in a fraction of

the space needed for the magnetic system.

This is the optical disk. Optical disks now on the market area of the same

size as record albums with a diameter of 20 cm, but a single optical disk has

a memory capacity of lGbite (G...1 billion, lbite...8bit). [Figures in

English as published]

The latent demand for CDs is said to reach 40 million units in Japan, with an

additional demand of 300 million units coming from the United States and

Europe. The market thus has potential to develop into a big market in the

post-VTR age. The 1986 output of CD players was at the level of 7 million

units, and the 1987 figure should surpass the 10 million mark. The 1986

production of optical-type VD players was 700,000 units. Consequently, the

combined CD and VD market for 1990 is considered certain to reach the level of

Y500 billion at the minimum.

Optical disks, on the other hand, have just taken off, so the market is only

at the level of Y1.2 billion, but when rewritable type devices make their

debut, they should garner to themselves an equivalent of a market share that

otherwise would have gone to magnetic disks, reaching Y500 billion in 1995.

3.6 Optical input/output devices

Laser printers and laser photoengraving devices are the most important

equipment of all optical input/output devices.

These devices, having a drum and a photosensitive material, work as follows:

A positive corona discharge in a darkroom gives the surface of the

photosensitive material a static electricity charge, thus making the surface

photosensitive. Next, the text to be copied is changed into an optical image

of bright and dark spots. When the image is subjected to radiation for

85
exposure, there follows a "generation and transportation" of an optical

carrier in those parts of the photosensitive material exposed by light beams

that passed through the bright spots, dissipating the surface electric charge

in those parts. Conversely, the electric charge in the dark spots that have

yet to be exposed remains there. When such a latent charge image is

impregnated with a toner of a reversed polarity by means of electrostatic

attracting force, it works like a printing font impregnated with ink. When a

copying machine is pressed hard against it, an image as clear as a printed

image can be produced. Once copying is completed, the toner and electric

charge remaining on the photosensitive material's surface are removed, and the

process is repeated again.

Laser printers are equipped with a laser oscillator for the exposure source,

and they come in the two types of gas laser printer based on HeNe (helium

neon) and semiconductor laser printer based on GaAsal, depending on the laser

source. Since gas laser printers use short wavelengths, they feature large

numbers of printing dots, thus assuring clear printed letters or graphics, but

they are expensive because they use a gas laser. Thus, gas laser printers are

for the high end of the market, while semiconductor laser printers are for the

low end of the market.

Liquid crystal shutter printers, although they are not based on lasers, are

beginning to show potential as a dark horse after semiconductor laser

printers.

Impact printing systems are becoming the mainstay in the existing printer

market worth about Y800 billion, and laser printers account for a mere 6.5

percent of the market, or Y50 billion.

But, helped by their high performance and with decreasing costs, laser

printers should achieve more than 30 percent share of the market, with sales

on the order of Y300 billion, by 1990.

3.7 Optical cards

In Japan, a group of 13 banks including The Sumitomo Bank, The Tokai Bank and

the Kyowa Bank is conducting an experiment in a service using cards that

incorporate both the cash card and credit card functions in Hikarigaoka area,

Nerima-ku, Tokyo, as part of the NMS (New Media Service).

Furthermore, optical cards developed by (Drexler) Technologies of the U.S. and

Dai Nippon Printing Co are emerging as the third ace.

These optical cards come in two types. The optical card developed by

(Drexler) is based on a method in which, as with CD and optical disk, the

recording surface of cards is pockmarked with pits (gelatin in the recording

layer is dispersed with silver grains, and melting of the silver grains leads

to the formation of the pits), while the one developed by Dai Nippon Printing

is based on a plane block recording system.

In plane block recording, a data memory layer consisting of a non-silver salt

pattern layer, three microns thick, and a reflective layer is sandwiched by a

86
protective layer and a substrate material layer. When a laser beam is shined

at it from directly above, instead of making pits the heat alters the

composition of the organic resin in the memory layer and the metal salt

precipitates at the time of electrolysis plating. The reflectance of light

stays at only 5 percent at where the metal precipitated vs 80 percent at where

no precipitation of metal took place, and the differences are read.

The card's memory layer consists of 812 (28 x 29) blocks, with each block

capable of storing 4 bits (520 bytes) of memory, so the total memory capacity

is 3376 Mbits (422 Kbytes). In other words, a single card can hold 160 pages

of A-4 text. it can also be used in combination with magnetic stripes with

ease. In the below are compared the three types of cards with respect to the

storage capacity and the costs of unit storage capacity.

Card type

Magnetic card

IC card

Optical card

Memory capacity

70-80 bytes

8000 bytes

422,000 bytes

Cost Cost-memory capacity

Y500 62.5 yen/byte

Y5000 0.6 yen/byte

Y300 0.0007 yen/byte

The optical card is advantageous in terms of memory capacity and memory

capacity/cost, but it has a disadvantage in that it is lacking in a erase and

rewrite capability.

The number of magnetic cards, including the 80 million cash cards, and credit

cards and shopping cards, in circulation at present is considered to be about

200 million. And it is estimated another 40 million or so magnetic cards are

printed annually, and this shows the extent of the potential market for

optical cards.

20,114/9365

CSO: 4306/6572 END

87