Development of Manufacturing Equipment
for D-WDM Related Devices
by Toshio Sakai *, Tomoaki Toratani *, Kazuhiro Miyazawa *,Mizuki Oike * and Koichi Miyazaki *The increasing demand for D-WDM (Dense Wavelength Division Multiplexing)
related devices such as optical devices or optical components requires manufacturing equipment to be more efficient in productivity, of higher quality and more compact.
Furukawa Electric has been developing many types of manufacturing equipment and testing
apparatuses for these D-WDM related devices. In this report, three types of manufacturing equipment are introduced: a fully automated scribing and chip-cleaving machine for cutting an LD(Laser Diode) bar into many chips, an LD chip aging apparatus, and the automated alignment
machine which is the core technology in optical component fabrication.
A reduction in cost of D-WDM related optical components is strongly being demanded by customers; in addition, new machines in this field are constantly being introduced into the market.
Therefore, we have to develop new machines which manufacture competitive products considering the various needs stemming from research and development groups and from manufacturinggroups. We are also planning to sell these machines to companies in Japan and overseas.

ABSTRACT1.

INTRODUCTION

The demand for D-WDM related optical devices and components is rapidly increasing, resulting in the need formass-production manufacturing facilities designed formore effective productivity, higher quality and compactness. Since Furukawa Electric manufactures optical semiconductors, the manufacturing equipment for these DWDM related devices that we have developed have lots oftechnical know-how that dedicated machine manufacturers lacking in.
Here, three types of machines are introduced: fully automated scribing and chip-cleaving machine for cutting an
LD bar into chips, aging apparatus, and automated alignment machine which is the core-technology in opticalcomponents fabrication.

2.

cleaving process in which the bar is cut into chips due tothe scribing effect. The existing scribing and chip-cleaving
process is divided into two processes: the scribing
process and the cleaving process. An operator is neededfor each process, therefore it is very inefficient. The fully
automated scribing and chip-cleaving machine combines
the scribing and chip-cleaving processes into one so thatthe new process is highly efficient and, as described later,

FULLY AUTOMATED SCRIBING AND
CHIP-CLEAVING MACHINE

2.1 Outline
This machine has been developed in order to fully automate the process of cutting an LD bar into chips. The bar
is cleaved from a wafer. This method includes a scribing
process in which the bar (LD chips are aligned along thebar axis) is scribed at each boundary of the chips; and a*

Production Technology Development Center, Plants andFacilities Dept.

Photo 1

Scribing and cleaving machine69

greatly improves the yield rate of the products. Photo 1
shows an entire view of the machine. This machine
includes three mechanisms: the precise positioning mechanism for cutting chips by image processing, the scribing
mechanism, and the cleaving mechanism. A bar is fixed
on the setting board using expandable adhesive sheet;then the bar is set on the chip-cleaving stage, and thechips are automatically cleaved simply by pushing thestart button.
2.2 Mechanism for Scribing Position Recognition
In the present scribing process, the first scribing positionof the chip has to be specified manually by the operator,
and the bar is then automatically scribed at a fixed interval. The operator, therefore, always has to manually specify the first position of each bar.
We have developed a new machine with an automatic
positioning mechanism for scribing using image processing. The bar image is captured by an CCD (Charge
Coupled Device) camera positioned above, and a position
is determined by pattern recognition; then position-correcting instructions are sent to the stage controller whichmoves in the x, y, and θ directions. If a suitable position is
not taken, position detecting and correction continue until
an appropriate cleaving position is selected.
2.3 Load Control Mechanism for Scribing
Scribing was usually done with a sharp-edged needle.
The new machine uses a circular blade, shown in Photo 2.
The circular blade can scribe a bar simply by pressing iton the cleaving position of the chips. The working point of
the circular blade is not restricted to one point, but any
position around the circle will do. Therefore, the blade
lasts much longer. Another advantage is that if one pointof the circular blade is damaged, other points are available by rotating the circular scriber several degrees; thus,
the process has a very high productivity.
Figure 1 shows the control mechanism of the scribing
force. The spring, which is fixed onto the stage, supports
the circular blade, the fixing arm and the weight. The

stage moves down to scribe the bar. When the stage
moves further down to the point where the circular blade
first comes into contact with the bar, the spring extends toapply the force onto the bar, which is a part of the total
force including the weight of circular blade, fixing arm andthe weight. The extension of the spring depends on theposition of the stage; this enables the operator to control
the scribing forces on the bar.
2.4 Cleaving Mechanism
The cleaving process was usually done manually. Afterscribing the bar, the cleaving process was carried out by
applying a force with some tool, such as a knife, from therear side of the bar. Ideally, chips should be cleaved into
mirror surface by applying a force on the position scribedin the former process. When using the knife for cleaving
chips, however, it is difficult to correctly set the knife-edge
into the rear of the scribed position of the bar to getenough chips with mirror surface.
A characteristic of the cleaving mechanism of the newmachine is that this machine can accurately apply a force
on the scribed position using measured data recorded
when scribing, thus resulting in accurate cleaving. The
cleaving mechanism of this machine, as shown in Figure
2, consists of an upper head with projections and a lower
block. The upper head accurately falls onto the scribing
position to press the bar, and the contact points of thelower block and the upper head act as fulcrum and pointof force, respectively, and then the bar is cleaved into
chips precisely at the scribed position. Equal forces areapplied on both the left and right side of the scribed line toobtain chips with smooth-surfaced cleavage.
Motor
WeightSpringScribing blade

Figure 1

Scribing mechanism

Figure 2

Cleaving mechanism

Upper head

Lower block

Photo 270

Scribing and cleaving stage

Furukawa Review, No. 19. 2000

3.

AGING APPARATUS FOR OPTICAL
DEVICES

3.1 Outline of Aging Apparatus
Information communications systems of today require
optical devices to be highly reliable. We are carrying out
strict screening tests on all manufacturing processes toassure the quality of our optical devices. In the chip manufacturing process, to be more specific, long-term reliability
tests are carried out for the chips in the can package, andin the butterfly-module manufacturing process, a much
more restrict evaluation tests are done on the modules.
For the aging apparatus used in the screening test,
highly accurate measurements and high reliability for the
long-term automatic measurements are required. It is also
necessary to upgrade the MMI (Man Machine Interface) inorder for the operator to set the machine, and collect andanalyze the data. In order to meet these requirements, wehave developed aging apparatuses in our factory andhave applied them in many of the manufacturing processes.
The features of the aging apparatuses are described
below in the sequence of power source circuit for LD, thermostatic chamber, optical receiver for PD (Photo Diode),
test board and computer system.

illuminated, APC is conducted on this LD and after the PD
moves to another LD, ACC is carried out at a current corresponding to the optical output. This sampling APC system uses a PD which has good temperature characteristics so as to restrict the aging effect by the PD to a minimum level. Occasionally, fluctuations in optical outputs
occur due to the mounting and dismounting of test boards
from the PD chamber during the aging test; however, thefluctuations are corrected by the automatic alignment
mechanism for stable aging.
3.4 Test Board
The aging apparatus is designed to save space in consideration of the large quantity of LDs' aging, which results ina yield of 560 to 640 channels/machine for the 1 A classLDs (Photo 3).
The advantage of our high-density mounting system
stems from its structure. The heat is dissipated from theLDs to cooling fins with minimized thermal resistance toproduce excellent results. (See Photo 4).

3.2 Power Source Circuit for LD
Power source circuits for LDs are provided in the range of
1 to 5 amperes to adapt to the circuit technology of our
optical amplifiers.
Depending on the application, two types of control systems for aging are used. One is the ACC (Automatic
Current Control) which keeps the load current to the LD
constant, and the APC (Automatic Power Control) whichkeeps the optical output from the LD constant. In the coreof the control system, a fast, high-performance 32-bit CPU
is mounted to carry out various measurements and controls such as high-accuracy APC or other measurements
necessary for aging.
3.3 Thermostat and PD Receiver
The thermostat consists of an LD chamber which accommodates test boards mounted with LDs and a PD chamber which accommodates PDs. The following two control
systems are adopted in the PD chamber, depending on
the application.

Photo 3Aging machine

3.3.1 Normal APC System
This is a test system normally adopted, in which PD units
as many as the LDs are arranged in the PD chamber.
Silica light-guide is mounted between the LD chamber and
the PD chamber. Light from the LD mounted on the test
board travels along the light-guide to the PD unit.
3.3.2 Sampling APC System
This system includes one chamber of LDs (40 to 160 pcs)
and one PD; the PD moves to the emitting facet of each
LD in turn. LDs mounted on the test board emit lightthrough heat-resisting glass to the PD. While the PD is

Photo 4

Test board for LD chip71

Windows NT
RS232C/485

Positioning mechanism control
Personal computer

Unit 1

Unit 2

Power source
control panel for LD driveCPU
40ch LD driver

LD chamber 1

CPU
40ch LD driver

140ch <PD-4>(20ch LD cassette x 7 sets)

PD signal

Unit 3PD signal

Unit 4PD signal

Thermostat and PD
positioning mechanismCPU
40ch LD driverCPU
40ch LD driver

LD chamber 4

PD signal
140ch <PD-4>(20ch LD cassette x 7 sets)

Unit 16CPU
40ch LD driver
PD signal
PD signal
converter for 4ch

Figure 3

PD chamber
Measuring PD positioning
mechanism
PD 1

Block diagram of aging machine for LD chip

3.5 Computer System
Regarding the reliability and maneuverability of the system, it uses Windows NT and specifically designed application software. Therefore, the setting operation andresponsivity control which are essential to the aging test
are realized through interactive operation with a personal
computer . As shown in Figure 3, this system contains thesetting of a power source circuit for LDs, gathering of test
data, and the control function for a positioning robot of PD(sampling APC system). The measured aging data aregraphically edited easily by the MMI function of the PC,
enabling it to transmit data to a host computer via LANs.

4.

FULLY AUTOMATED ALIGNMENTMACHINE

4.1 Outline of the Development
The alignment process is one of the key processes in
improving productivity (shortening of tact time, non-skilled
operation) of manufacturing machines for optical device
modules. In the alignment process, the working timeneeded for manual alignment operation varies greatly
depending on the operator's skill. The automated aligning
controller available today has a long tact time causing abottleneck in productivity. We have, therefore, developed
an automated alignment machine with a much shorter tact
time. This machine has high performance and is inexpensive, and not only is used in our factories but also is soldto users in foreign countries (Photo 5 is a fiber alignment
machine for in-house use).
The following is an explanation of the optical devicealignment and assembly machine and the features of ourautomated alignment machine.

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Photo 5Fiber alignment machine

Measuring PD positioning
PD 4
mechanism

4.2

Alignment and Assembly Machine for Optical
DevicesIn the field of optical devices, "alignment" means the spatial mating of optical axes between light-emitting andreceiving elements, between optical fibers, and between
light emitting/receiving elements and optical fibers. Thisalignment is done by setting a total of 6 degrees-of-freedom in position; optical axis direction (z-axis); two axes
directions which are perpendicular to the z -axis ( x - yplane); and three rotating angles around each axis (θx, θy,θz). Usually, the positioning of rotational directions of θx,
θy, or θz is mechanically compensated (i.e., facet alignment mechanism, visual setting of θz, etc). In practice, xyz
3-axes alignment or xyz θz 4-axes alignment are used.
The method for aligning the elements or fibers is as follows: optical elements or fibers are held opposite to eachother; one emits light and the other moves in the space toreceive light, searching for a position with maximum optical coupling power.
4.3 Features of Automated Alignment Machine
The automated alignment machine uses "5 points alignment" which searches for the peak of the light intensity
distribution in the xy-plane that closely resembles a twodimensional curved surface. This method is for generalpurpose use and the tact time is relatively short; therefore,
it is available for various alignment applications. The optical intensity distribution along the z-axis direction is notvery steep compared with the xy-plane, while the fluctuation of the intensity is great; therefore, additional ideas
must be adopted in order for the peak not to be in local
optimum.
The configuration of the hardware is as follows: stage
control operates the pulse driver with the control board
built into a personal computer to make the operation
faster; the pulse driver can give a resolution of 0.004 to 1
µm/1 pulse by micro-step regulation. The optical power
data is taken from GP-IB communications and also fromthe AD board to make the measurement faster.

Furukawa Review, No. 19. 2000

By adopting these ideas, the tact time was shortened by
40% compared to conventional alignment machines. The
price of the machine is much lower than automated alignment machines on the market due to the use of off-theshelf parts available.
The most advantageous point of in-house manufacturing of the alignment machine is that it has made it possible to freely customize alignment operation in addition toincreasing productivity by tact-time shortening or cost-cutting. In practical designing, it is necessary to understandthe features of light-intensity distribution that various applications (fiber-alignment, lens- alignment, ferrule alignment, etc.) are dealing with so as to customize the automated alignment machines.The features of light-intensity
distribution may be steep or not steep, and smooth or fluctuating. If fluctuating, whether measurement errors orother physical factors such as light interference cause it.
This machine has the advantage of being able to respondto all in-house applications.

5.

CONCLUSION

We have developed mass-product fabrication machines
and testing equipment for D-WDM related optical devices,
resulting in devices of high, stable quality and high productivity.
The field of D-WDM related optical devices is now growing larger and larger and new devices are always being
introduced. We have to make an effort to develop new
machines for our competitive D-WDM related opticaldevices considering the needs of our development andmanufacturing sectors. Furthermore, we are planning tosell the machines to users in our country as well as overseas.
Manuscript received on October 21, 1999.

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