1/32

COMMISSION D: Electronics and Photonics (November 2004 October 2007)
Edited by Hiroyo Ogawa and Masahiro Muraguchi
The fields of Electronics and Photonics are huge and include many active sub-fields therein. We
have summarized the trend of these technical fields in the last several years, which includes thetime period of the interest in this report, years from 2004 to 2007. Japanese leading researchers
overviewed recent conspicuous progresses of their respective sub-fields.
The following is a list of the sub-fields that the chapter editors have taken up.
D1. Electro-optic Sensing Devices and Systems
M. Tsuchiya
National Institute of Information and Communications Technology
D2. Semiconductor Lasers (Light sources for optical communication)
Mitsuru Naganuma
Teikyo University of Science & Technology
D3. Tbps optical modulators
Tetsuya Kawanishi
National Institute of Information and Communications Technology
D4. Photonic Signal Processing
Tazuko Tomioka
Toshiba Corp.
D5. THz Technology
Tadao Nagatsuma
Osaka University
D6. Silicon Devices
Kazukiyo Joshin
Fujitsu Laboratories Ltd.
D7. A brief view on the ultra wideband (UWB) status in Japan
Kenichi Takizawa
National Institute of Information and Communications Technology
D8. Body Area Network Devices
Kiyoshi Hamaguchi
National Institute of Information and Communications Technology
D9. Millimeter-Wave Antennas
Keren Li
National Institute of Information and Communications Technology

D1. Electro-Optic Sensing Devices and Systems

2/32

Abstract
Here, an overview on recent advance of electro-optic (EO) sensing devices and relevant
systems is provided with emphases on those in R&D phases in Japan. After an introductorypart, some categorizations for the EO sensing are given. This is aimed at readers’ better
understanding on the relevant technical trends and their recent progresses in the fields. Someeye-catching demonstrations are explained as pioneering examples for the novel EO sensing
schemes. In other words, some strong emphases are cast over the devices and systems
described here, in which fundamental issues of the EO sensing paradigm have been ultimately
pursued, while some other recent practical developments are missing.
I.

Introduction[1] EO sensing devices and systems
Among many sensing devices and systems, those based on the electro-optic (EO) effect, Pockels
effect in other words, are rather noteworthy recently [1] and, hence, we focus ourselves within
this sort of technologies here. The reason why the EO sensing devices and systems are
attracting considerable amounts of technological attentions could be that their fundamental
features be essential to the evolution of information and communications technologies in the last
decade as well as in the future.
As well known, accelerating increase in demand for ultimate speeds both in fiber-optic andwireless communications technologies have been prominent. More and more requirements
will be cast henceforth on the developments of higher speed fiber optic networks, broader
bandwidth wireless access networks, and their efficient and cost-effective convergence.
Advanced measurement techniques for devices, modules, and circuits of high speed and highly
dense packages have been and will be demanded in this context. The scheme of EO sensing
devices and systems have provided and will provide some attractive measurement features forthis purpose as listed in the followings:
a． Ultra-high speed
b． Very low invasivenessc． Sub-wavelength spatial resolutions.
d． Distant lead wire configurations(a) An EO measurement bandwidth is not restricted by electrical circuit parameters but by the
response speed of the EO effect, which is inherently high-speed. Even THz frequencies are in
the range.
(b) No metal electrodes in probe heads are necessary in the EO sensing scheme and, therefore,
the measurement circumstances can be metal-free. This leads to significant reduction inmeasurement invasiveness to devices and circuits to be analyzed. Additional reduction ofinvasiveness is possible if needed volume of high-index EO crystal is compressed down to thoseof optical beams.
(c) A dominant factor for the spatial resolution of the measurements is the sensitive volume
defined within an EO crystal [2], which is usually much smaller than wavelengths of radio
signals to be measured. This feature provides a measurement scheme, which is impossible
without photonic methods: measurements with a sub-wavelength spatial resolution provided
without serious invasiveness. This is attractive for the microscopic analyses of highly dense
circuits.
(d) In many RF measurement methods, lengths of lead wires are restricted and to be shortenough to avoid attenuation of detected signals and interference caused by metal wire cables:
presence of long lead wire cables itself causes possible malfunctions of measurements. Opticalmethods, especially fiber optics, can relax this stringency and enlarge the degree of freedom inthe measurements.
[2] Technical trend

3/32

As shown in Fig. 1, there are two kinds of categorized functions in EO sensing systems: EO
measurements and EO imaging. The former is rather conventional while the latter is new.
Regarding the former, relevant devices are categorized into two types: optical waveguide typeand optical probe type [1]. Because of the stability and sensitivity, the former with metalelectrodes has been in the marketplace already although some drawbacks exist regarding theabove-mentioned benefits. Hence, hereafter, we exclude commercially available EO sensing
devices and we concentrate ourselves within those in the R&D phases together with EO
imaging scheme.
In other words, we are going to depict here those having some eye-catching demonstrations
during the time period from November 2004 to October 2007, with special emphases, in whichsome fundamental features of EO sensing scheme have been ultimately pursued. Thosecorrespond to the categories “probe” and “image sensor” in Fig. 1. Also, one should note that
we have had the third and fourth generation of the EO sensing configurations, which are indeed
the configurations in which recent progresses have been made intensively. In more details, thefollowing four examples are described below. (a) A fiber-edge EO sensing device with directly
deposited EO material on its fiber facet, which provides an ultimately small size of probe head.
(b) An EO probe with an EO crystal of an ultra-high Q optical cavity, which brings about theever highest EO sensitivity. (c) An EO sensing system with the ultra-parallel nature ofphotonics, which enables the real-time imaging of RF electrical field distributions with a highdefinition for the first time. (d) With the real-time EO imaging system, a demonstration was
performed for aqueous sample investigation by electromagnetic wave images.

EO sensing system
EO measurement
WaveguideProbe
EO imaging
Scanning
Image sensor
Fig. 1 Categories of EO sensing systems and relevant devices
II.

EO sensing of RF signals[1] Principle and categorization of schemes
Figure 2 shows schematically the basic elements and principle of EO measurements [3]. A
probing light beam is incident from the left to an EO crystal. An applied electrical field E
gives rise to instantaneous index change of the crystal through the EO effect. The resultant
polarization modulation on the light beam is then transformed to the intensity modulation.
This is brought about by a polarizer. The relationships among the polarization states of the
probing light beam and the orientations of EO crystal and polarizer are optimized so that the EO
sensitivity is maximized. This optimization is performed with properties of the light source4/32

and photo-detector taken into considerations.

Polarization
modulation
Intensity
modulation
polarizer→
E

Pockels effect
EO crystal(ZnTe etc.)

Fig. 2 Basic elements and principle of EO measurements
Shown in Fig. 3 is a categorization of the EO sensing schemes performed regarding thevariety of light sources and EO signal detection techniques. The EO sampling scheme [3] isthe most well known, in which very short light pulses are indispensable and a slow photodetector can be used. The timing control of the sampling pulses is an issue. It is powerfulwhen one measures temporal waveforms of ultra high-speed signals. The EO heterodyne is analternative to the EO sampling scheme. A probing light beam of high frequency sinusoidal
modulation, an optical LO (OLO) signal in other words, is necessary and frequency downconversion is carried out at the EO crystal in the system shown in Fig. 2. An optical IF signal
resultantly generated is detected by a slow photo-detector, which corresponds to the highfrequency component of interest. Therefore, the EO heterodyne scheme is essentially suitable
for a spectrum analyzing measurement and, therefore, for a measurement of wirelesscommunications apparatus. The third category is the direct EO measurement scheme, in whicha continuous wave probing light beam is used. While requirements for light sources are muchrelaxed, a high speed photo-detector and subsequent high speed measurement instruments areneeded. Except for those outer instruments, the setup could be beneficially simple.

5/32

EO measurements

EO Sampling
Temporal waveform measurements with pulsed light

EO Heterodyne
Spectral measurements with high frequency OLO

Direct EO Measurement
Measurements with CW-light and high-speed instruments

Fig. 3 Categories of EO measurements[2] Generations of EO sensing system configurations
It might be interesting to trace the historical evolution of measurement technologies for EO
sensing scheme in correspondence to the basic elements shown in Fig. 2 and relevant system
configurations. Figure 4 shows four stages of generations for the EO measurement
configurations.
In the first generation, a large pulse laser such as an Ar+ laser pumped mode-locked dye laser
was placed on a large optical bench and was used for EO measurements. Thus, the laser pulse
source was the principal issue while other elements were rather commonly arranged.
In the second generation, some variation was brought about regarding the laser pulse source,which is down-sizing. On the basis of developments of diode laser based pulse sources andfiber-optics in late 80s and 90s, some compact, stable, and easy-to-operate light sources became
available and were incorporated into the EO measurement configurations. The paradigm thus
shifted from systems on optical tables to desk-top measurement instruments. The shift was
based on the innovation of pulse light source.
In the third generation, configurations around EO crystals have been modified significantly.
Probe heads were miniaturized and the role of optical fiber was set two-fold: an EO crystal
holder and a waveguide for a probing light beam [4]. Those were brought about by thedevelopments of fine fiber-optics and micro-optics. As results, the alignment-free EO probehead was realized and mobility of the probe head was also. In addition, the low-invasive nature
was enhanced.
In the fourth generation, the trend of EO crystals has been in an opposite direction. Rather
large EO plate has been utilized for the scheme of EO imaging. This is indeed what has
happened in the time period of this national report’s interest. One of the most significant
breakthroughs regarding this aspect is the introduction of ultra-parallel nature of photonics [5-8],
which will be described in more details later.

6/32

EO sensing system
Generation 1
Large pulse laser and space optics

Generation 2
Semiconductor/fiber laser with fiber-optics

Generation 3
Fiber-edge EO probe

Generation 4
EO plate for imaging

Fig. 4 Generations of EO sensing systems
III.
Fiber-edge EO sensing device
One of the ultimate EO sensing devices is those fabricated on the facet of optical fibers [9-15].
This configuration gives highest spatial resolutions of the EO measurements, which are
determined by the beam diameter of optical fiber and the thickness of the crystal. Minimum of
the resolution volume has been thus as small as 10x10x10 μm3.
The conventional method to fabricate those fiber-edge EO sensing devices is rather
straightforward, simple and difficult. A piece of EO crystal was adhered to the optical fiber
facet. In some cases, a piece of EO crystal bonded to a glass wafer was used. Unfortunately
enough, the size reductions of the EO crystals thus adhered are limited because of difficulties intheir handling procedures. The crystal sizes are usually larger than optical fiber diameters (125μm) and consequently degrade much the easy-to-insert-anywhere feature of the fiber-edge
scheme.
Recently, Iwanami et al. has made a breakthrough regarding this aspect of optical fiber based
EO sensing devices [16-18]. They have succeeded in direct depositions of EO crystal (leadzirconium titanate: PZT) films on an optical fiber facet. A scanning electron micrograph of adevice thus fabricated is shown in Fig. 5. One should note that the area of the EO crystal isalmost the same as that of an optical fiber facet or even smaller. This feature is considerably
attractive as follows. (a) The shape and size of the EO crystal, which has been a limiting factorof the EO probe head size, is no longer larger than the optical fiber facet diameter. Hence, theeasy-to-insert-anywhere feature of the fiber-edge scheme is highly enhanced. (b) One canreduce the thickness of the crystal down to the nanometer range if desired. In combination
with optical fibers of finer core diameters, the minimum sensitive volume can be reduced down
by one order of magnitude or more. It may lead to creation of new EO measurement paradigm.
Fig. 6 shows a schematic of the aerosol deposition method, which was utilized for the EO
sensing device fabrication.

7/32

PZT film

Opticalfiber

Fig. 5 Lead zirconium titanate (PZT) deposited fiber-edge EO probe

optical fiber

X-Y-Z θ stagegas bottle

substrate holder
fiber fixture
nozzleaerosol chamber(vibrating)Fig. 6IV.

tube

depositionchamber

vacuum system

PZT powder

PZT-deposition method for fabrication of fiber-edge EO probe

LN disk resonator for EO sensing
One of the most effective methods to improve the sensitivity of an EO probe is to enlarge
the interaction length between a light-wave and an electrical signal to be measured.
Usagesof optical cavities are fairly effective for this purpose since the interaction length is effectively
enlarged by a cavity quality factor (Q factor) [9], provided that the measurement bandwidth
suppression given by the corresponding photon lifetime of cavity can be managed somehow forpractical measurements. Recently, as well known, high-Q optical cavities are available, mainlyon the basis of optical disk resonator scheme and its whispering gallery mode (WGM).
Especially, It has been reported that a cavity having a Q factor of 108 or more can be made of an
EO crystal [19][20].
Sasagawa and Tsuchiya have performed an experiment in which such a high-Q cavity isapplied to the EO sensing scheme [21-24]. The LiNb3 (LN) disk resonator which they made isshown in Fig. 7 and the relevant experimental setup is indicated in Fig. 8. The axis of disk
rotation symmetry is parallel to the c-axis of LN crystal. A sensing light beam is coupled to
the LN disk resonator trough a rutile prism, which is shown in the upper part of Fig. 7. The
radius of the disk is 3.3 mm while its rim curvature radius is 3.3 mm. The LN disk resonator,
an EO sensing head in other words, was allocated on a micro stripline as shown in Fig. 8, which
is a device-under-test (DUT) in the measurement. Thus, some evanescent waves of RF signals

8/32

in the stripline were measured and the sensitivity was investigated.
Figures 9 show (a) EO signal power thus obtained at the RF spectrum analyzer in Fig. 8,
which is plotted against the RF power launched to DUT, and (b) a temporal waveform measured
by a oscilloscope for a photonically down-converted IF signal at 500 kHz. The frequency ofthe original RF signal is 6.72 GHz and the impedance of the stripline is 50 Ω . Note that theestimated minimum detectable RF power on the stripline is as low as -60 dBm, whichcorresponds to the minimum detectable voltage of 0.13 mV/Hz1/2. Those values indicate thehighest EO sensitivity ever reported. Such a high sensitivity allows one to observe thetemporally sinusoidal waveform with a digital oscilloscope as shown in Fig. 9 (b), which israther difficult in the EO sensing scheme conventionally.

Fig. 7 A photograph of LN disk resonator together with a lutile prism in the back.
prism is for the optical coupling between WGM and a sensing light beam..

Polarizaiton
Controller(50Ω stripline)

disk

stripline

Fig. 8 Experimental setup for the disk resonator EO probeTheEO signal (dBm)

9/32

-60

RF frequency 6.72 GHz
IF frequency 500kHz
Optical power 20.0 dBm

-80
-100
-120

Noise level: -126 dBm

-60

-40

-20

0

20

Input RF power (dBm)

(a)

(b)
Fig. 9 EO signal power plotted against RF power (a).
signal (b).
V.

Temporal waveform of the RF

Live Electro-optic Imaging (LEI)
One of the most eye-catching inventions in this field is the realization of ultra-parallel RF
signal measurement scheme and its application to the real-time visualization of RF electricalfield distributions. This was done by Sasagawa and Tsuchiya, and the technology is called as
LEI [5-8]. The degree of parallelism is 10,000, which is outstanding in comparison with theconventional single channel nature in standard RF measurements. The availability of 10,000
parallel RF measurements thus obtained has led to the real-time visualization of RF field
distributions, live imaging in other words.
Shown in Fig. 10 is the latest prototype of LEI camera provided by Sasagawa, Kanno, andTsuchiya. The area of the prototype base is as small as that of A4 letter paper size andtherefore the prototype is portable. The insets of Fig. 10 are top view pictures of a patch
antenna taken simultaneously by the camera, which are by a CCD image sensor (left) and a LEI
view (right), respectively. One should note that intense electrical fields are observed clearly on
the four corners of the patch as conventionally indicated by the electromagnetic theory.
The performance specifications of the prototype are as follows. The size of view area,
which is located on the top surface, is 25 mm x 25 mm. Thus the device-on-the-top
configuration is brought about, which enables the face-down measurement scheme andeventually easy-and-prompt handling of DUT for its RF field visualization. The observation
bandwidth is as high as 10 GHz and the highest frame rate is 30 frames per second.
A series of images shown in Fig. 11 are taken from a LEI video stream and indicate a
temporal evolution of the LEI view for the patch antenna. Here the LEI video stream was10/32taken in the real-time mode with the phase evolution imaging scheme. This was made possible
by intentional insertion of a slight discrepancy in frequencies of the DUT signal and the LO
signal, which is shown in Fig. 12 in more details. Indeed, it is clearly seen that the phase of
DUT electrical field proceeds as the time goes.
Figure 12 shows schematically the optical system of the LEI camera. One can see here that it
includes rather new elements of EO sensing scheme: the image sensor scheme listed in Fig. 1,
the EO heterodyne scheme listed in Fig. 3, and an EO plate of the fourth generation shown in
Fig. 4.

Fig. 10 LEI prototype with CCD image (left) and LEI image (right) of a patch
antennaFig. 11 A temporal evolution of LEI view in the phase evolution real-time
imaging mode.

11/32

Fig. 12 Optical system of LEI camera
VI.

Aqueous EO imaging
Kanno, Sasagawa, and Tsuchiya have shown an interesting demonstration of LEI camera: its
application to aqueous EO imaging [25]. The imaging configuration is shown in Fig. 13,
where an aqueous sample is placed in front of the sensing area of a LEI camera. Thisconfiguration enables one to perform instantaneous characterization of aqueous specimens.
Examples are shown in Figs. 14, in which high resolution images of transmitted microwave
intensity and phase distributions for a water capsule sample was successfully obtained. Notethat those were obtained in less than one second. Dramatic changes in EO intensity
components at the edges of the sample were visible, which is possibly due to diffraction of theincident microwave. The phase components clearly show the shape of the sample on the basisof absorption and phase delay. Higher contrast in images was obtained by the combination of
the EO intensity and phase components: phasor imaging.

Fig. 13 Concept of aqueous EO imaging with LEI camera

12/32

Fig. 14

CCD images and LEI images for a water capsuleVII. References[1]
M. Tsuchiya, “Methods for electromagnetic field measurements with advantageous
optical features employed”, the Review of Laser Engineering, Vol. 33, No. 6 June 2005, pp.
365-372 (in Japanese).
[2]
S. Wakana, E. Yamazaki, M. Iwanami, S. Hoshino, M. Kishi and M. Tsuchiya, “Studyof a Crystal Size Effect on Spatial Resolution in Three-Dimensional Measurement of Fine
Electromagnetic Field Distribution by Optical Probing”, Japanese Journal of Applied Physics,
Vol. 42, No. 10, pp. 6637-6640 (October, 2003)[3]
J. A. Valdmanis, G .Mourou, and C. W. Gabel, “Picosecond electro-optic samplingsystem”, Applied Physics Letters, Vol. 41, No. 3, pp. 211-212 (1982).
[4]
S. Wakana, T. Ohara, M. Abe, E. Yamazaki, M. Kishi, and M. Tsuchiya "Novelelectromagnetic field probe using electro/magneto-optical crystal mounted on an optical-fiber
facet for microwave circuit diagnosis" Technical Digest of IEEE MTT-S International
Microwave Symposium 2000 (IMS2000), Boston, TH3C-3, pp. 1615-1618 (2000).
[5]K. Sasagawa, and M. Tsuchiya: “Real-time monitoring system of RF near-field
distribution images on the basis of 64-channel parallel electro- optic data acquisition”, IEICEElectron. Express, vol. 2, no. 24, pp. 600-606, December 2005.
[6]
K. Sasagawa, T. Kawanishi, and M. Tsuchiya: “10,000 parallel heterodyne system for
instantaneous photonics- based acquisition of near-fields images over microwave
devices/circuits”, Asia-Pacific Microwave Conf. 2006, FR2C-5, pp. 1587-1590, December 2006.
[7]
K. Sasagawa, A. Kanno, T. Kawanishi, and M. Tsuchiya: “Live electro-optic imaging of
microwave near-fields via ultra-parallel photonic heterodyne”, Int. Microwave Symp. 2007,
WE1F-05, pp. 401-404, June 2007.

13/32[8]
K. Sasagawa, A. Kanno, T. Kawanishi, and M. Tsuchiya, “Live electro-optic imaging
system based on ultra-parallel photonic heterodyne for microwave near-fields,” IEEE Trans.
Microw. Theory Tech., vol. 55, no. 12, pp. 2782-2791, December 2007.
[9]
S. Wakana, T. Ohara, M. Abe, E. Yamazaki, M. Kishi and M. Tsuchiya, "Fiber edge
electro/magneto-optic probe for spectral domain analysis of electromagnetic field", IEEE
Transaction of Microwave Theory and Techniques, Vol. 48, No. 12, pp. 2611-2616 (2000).
[10]
T. Ohara, M. Abe, S. Wakana, M. Kishi and M. Tsuchiya, "RF Intensity mapping basedon electro-optic spectrum analysis", Technical Digest of Japan-Korea Joint Workshop on
Microwave Photonics, Osaka, W2-8, pp. 66-70 (2000).
[11]
T. Ohara, M. Abe, S. Wakana, M. Kishi, M. Tsuchiya, and S. Kawasaki, "Twodimensional field mapping of microstrip lines with a band pass filter or a photonic bandgap
structure by fiber-optic EO spectrum analysis system", Technical Digest of Microwave
Photonics 2000 (MWP 2000), Oxford, WE2.17, pp. 210-213 (2000).
[12]
E. Yamazaki, S. Wakana, M. Kishi and M. Tsuchiya, "10 GHz－Class Magneto－
Optic Field Sensing with BiRIG Rotation Magnetization Employed", Japanese Journal ofApplied Physics, Vol.41, Part 1, No.2A, pp.904-907 (2002).
[13]
E. Yamazaki, S. Wakana, M. Kishi and M. Tsuchiya (Invited), “High Frequency
Magneto-Optic Probe Based on BiRIG Rotation Magnetization” , IEICE Transactions on
Electronics, Vol. E 86-C, No. 7, pp.1338-1344 (July, 2003).
[14]
S. Wakana, E. Yamazaki, S. Mitani, H. Park, M. Iwanami, S. Hoshino, M. Kishi and M.
Tsuchiya, “Performance Evaluation of Fiber-Edge Magneto-Optic Probe” , IEEE Journal ofLightwave Technology, Vol. 21, No. 12, pp. 3292-3299 (December, 2003)[15]
M. Iwanami, E. Yamazaki, K. Nakano, T. Sudo, S. Hoshino, S. Wakana, M. Kishi and M.
Tsuchiya, “ Magnetic Near Field Measurements over LSI Package Pins by Fiber-Edge
Magnetooptic Probe”, IEEE Journal of Lightwave Technology, Vol. 21, No. 12, pp.3273-3281(December, 2003)[16]
M. Iwanami, M. Nakada, H. Tsuda, K. Ohashi, and J. Akedo, "Ultra Small Electro-optic
Field Probe Fabricated by Aerosol Deposition", IEICE Electronics Express, Vol. 4, pp. 26-32(2007)[17].M. Iwanami, M. Nakada, H. Tsuda, K. Ohashi, and J. Akedo, "Ultra Small Fiber-Optic
Electric Field Probe Fabricated by Aerosol Deposition", Proc. 2007 Asia-Pacific Microwave
Photonics Conference (AP-MWP 2007), pp. 165-168 (2007)．
[18]
M. Iwanami, M. Nakada, H. Tsuda, K. Ohashi, and J. Akedo, "Ultra Small Magnetooptic Field Probe Fabricated by Aerosol Deposition", IEICE Electronics Express, Vol. 4, pp.
542-548 (2007).
[19]
D. A. Cohen, M. Hossein-Zadeh and A. F. J. Levi, “Microphotonic modulator for
microwave receiver”, Electron. Lett. Vol. 37, pp. 300-301 (2001).
[20]
V. S. Ilchenko, A. A. Savchenkov, A. B. Matsko, and Lute Maleki, "Nonlinear Optics
and Crystalline Whispering Gallery Mode Cavities," Phys. Rev. Lett. 92, 043903 (2004).
[21]
K. Sasagawa, and M. Tsuchiya, “An Electrooptic Sensor with Sub-millivolt Sensitivity
Using a Nonlinear Optical Disk Resonator,” Int. Topical Meeting Microwave Photonics(MWP2005), F3-5, pp. 355-358, Seoul, Korea, Oct. 12-14, 2005.
[22]
K. Sasagawa, and M. Tsuchiya, “Stabilization of whispering gallery resonance forhighly sensitive EO sensor,” Contemporary Photonics Technol. (CPT2006), Tokyo, Japan, Jan.
12-14, 2006, G-4, pp. 155-156.
[23]
K. Sasagawa, and M. Tsuchiya, “A LiNbO3 disk resonator with a SiO2 cladding layer
and proximate electrodes,” 2006 Conference on Lasers and Electro-Optics (CLEO 2006), Long
Beach, CA, May 21-26, 2006, CFC4.
[24]
K. Sasagawa, and M. Tsuchiya, “Coating of SiO2 on a LiNbO3 optical disk resonator,”Contemporary Photonics Tech. 2007 (CPT2007), Tokyo, Japan, Jan. 10-12, 2007, G-11.
[25]
A. Kanno, K. Sasagawa, and M. Tsuchiya, “Instantaneous microwave transmission

14/32

imaging of aqueous samples,” 2007 International Topical Meetings on Microwave Photonics(MWP 2007), Victoria, BC Canada, Oct. 3-5, 2007, Th-3.5.

D2. Semiconductor Lasers (Light sources for optical communication)
Semiconductor laser is a key device both in the core and the periphery networks carrying
explosively increasing Internet traffics. The transmission capacity of the each channel of
WDM system has been raised up to meet the increased traffics. This section pays attention todevelopment of the light sources for the up-to-date optical communication networks,
categorizing 4 application fields depending on transmission distances.
1. The ultra-short haul (<1km) transmission
The systems using the combination of the Fabry-Perot laser and the multimode fiber (MMF)
are developed, which are capable of 10Gb/s bit rate with 300m distance (IEEE802.11aq)[1].
Since reduction of the cost of light source assembly is the most important issue the verticalcavity surface-emitting laser (VCSEL) is a promising light source[2]. Characteristics ofdriving current vs. light output of VCSEL chip can be measured on wafer because its cavity isvertical to the wafer surface, which pushes down the overall cost. Transmission distance andbit rate of VCSEL are typically less than 600m and 1Gb/s, respectively.
2. The short to medium haul (1-25 km) transmission
Since the cost issue is still important even for the medium haul system the distributed
feedback (DFB) laser is used under direct current modulation scheme. However the lasing
frequency fluctuation during dynamic modulation (chirping) is unavoidable, which is caused byinjection current change followed by carrier density and refractive index change in active region.
This results in transmitted waveform distortion because the wavelength dispersion exists even ina single mode fiber (SMF). One of the solutions of this problem is to use DFB laser emitting
1.3-micrns wavelength, in which the wavelength dispersion of SMF is nearly zero.
The light source free from temperature control reduces substantially the cost of the system.
Carrier overflow from the quantum well consisting of the active layer degrades temperature
characteristics. Aluminum based mixed crystal is used instead of Phosphorus based one toachieve large electron barrier height of quantum well to prevent the carrier overflow. The
dynamic single mode operation at temperature rage of –40 to 85 degrees Celsius is achieved by
Al based laser and applied 10Gb/s system.
3. The medium to long haul (25-80km) transmission
The narrower line-width of optical source is demanded as longer transmission length. To
address this request the external modulator is used with cw DFB laser. For the medium haulsystem the semiconductor electro-absorption (EA) modulator is used as the external modulator
and monolithically integrated with DFB laser. EA modulator based on the Quantum Confined
Stark Effect (QCSE) has electric field dependent sharp absorption edge and is capable of morethan 10dB extinction ratio even with 200 microns device length, which realizes small opticalsources. Moreover, layer structure of EA modulator is similar to that of the laser, which makes
it easy to integrate monolithically each other and to reduce the fabrication cost. On the other
hand there still remains instantaneous frequency chirp caused by a refractive index change upon
applied electric field, which limits transmission length. Recently EA modulator with special
core structure is developed and successfully applied to the system with the fiber dispersion of
1600ps/nm (corresponding to 80km-SMF). The integrated light source with the temperature
control free laser is developed and realized the operation temperature of 90 degrees Celsius[3].

15/32

4. The long to ultra-long haul (>80km) transmission
The limitation coming from the chirping characteristic is much more strict for thistransmission length with more than 10Gb/s rates. The Mach-Zehnder (MZ) modulator is usedinstead of the EA modulator. A MZ modulator consists of dielectric material LiNbO3 isgenerally used for the practical systems because of its chirp-less characteristics. However,there remain some difficulties such as large size, large driving voltage, and drifting of driving
voltage balance. To address these problems the semiconductor MZ modulator is developedwith a footprint size comparable to that of a semiconductor laser and capable of 40Gb/s
modulation[4].
As an advanced structure the DQPSK modulator composes of two MZ modulators isdeveloped and applied to the 80Gb/s modulation experiment[5]. The semiconductor integrated
light sources including modulators, lasers and other photonic devices are promising for the
future advanced communication networks[6].
References[1] Y. Kurihara et al., “10Gbit/s FP-TOSA and PIN-ROSA for 10GBASE-LRM application”,
OFC06, Technical Digest, OThN4, 2006.
[2] N. Nishiyama et al., ”1.3 and 1.55-mm InP-based VCSELs for digital and radio signaltransmission”, OFC07, Technical Digest, OMK4, 2007.
[3] S. Makino et al., “Wide temperature (15C to 95C), 80-km SMF transmission of a 1.55-mm,
10-Gbit/s InGaAlAs electroabsorption modulator integrated DFB laser,” OFC07, Technical
Digest, OMS1, 2007.
[4] K. Tsuzuki et al., “1.3-Vpp push-pull drive InP Mach-Zehnder modulator module for 40
Gbit/s operation,” ECOC '05, Technical Digest, Th2.6.3, pp. 905-906, 2005.
[5] N. Kikuchi et al, “80-Gbit/s InP DQPSK modulator with an n-p-i-n structure,” ECOC2007,
Technical Digest, 10.3.1, vol. 4, pp. 143-144, Sept., 2007.
[6] T. Yasui et al., “Lossless 10-Gbit/s InP n-p-i-n Mach-Zehnder modulator monolithicallyintegrated with semiconductor optical amplifier,” OFC’08, Technical Digest, OThC5, 2008.

D3. Tbps optical modulators
Optical modulators using electro-optic (EO) or electro-absorption (EA) effect play importantroles in high-speed optical communication systems. Recently, over 20Tbps optical fibertransmission was demonstrated by using integrated lithium niobate (LN) optical modulators forultra high-speed differential phase shift keying (DQPSK) signal generation [1, 2]. Intensity
modulation (IM) and on–off keying (OOK) are commonly used in commercial systems.
However, recently, various types of modulation techniques, for example, differential phaseshift-keying (DPSK) [3], DQPSK [4–7], amplitude- and phase-shift-keying (APSK) [8, 9],frequency-shift-keying (FSK) [10–14], single-sideband (SSB) modulation techniques [15]–[17],etc., were investigated to obtain enhanced spectral efficiency or receiver sensitivity in opticaltransmission systems. Orthogonal modulation techniques with OOK and FSK or OOK andDPSK are also attractive for optical labeling in optical systems [12, 18, 19]. Integrated LN
modulators, such as dual-parallel Mach-Zehnder modulators (DPMZMs), quad-parallel MachZehnder modulators (QPMZMs), etc., can generate advanced modulation format signals, suchas high speed 16QAM (see figure 1), whose constellations are complicated [20, 21]. Precise
lightwave control was also investigated to achieve pure optical clock signal generation andhigh-performance digital modulation [22, 23].

16/32

Fig.1 Optical 16-QAM signal generation using a QPMZM [20][1] A. H. Gnauck, G. Charlet, P. Tran, P. J. Winzer, C. Doerr, J. Centanni, E. Burrows, T.
Kawanishi, T. Sakamoto, K. Higuma, “25.6-Tb/s C+L-Band Transmission of PolarizationMultiplexed RZ-DQPSK Signals,” presented at the OFC 2007, Postdeadline Paper 19[2] H. Masuda, A. Sano, T. Kobayashi, E. Yoshida, Y. Miyamoto, Y. Hibino, K. Hagimoto, T.
Yamada, T. Furuta, H. Fukuyama, “220.4-Tb/s (204 × 111 Gb/s) Transmission over 240 km
Using Bandwidth-Maximized Hybrid Raman/EDFAs,” presented at the OFC 2007, Postdeadline
Paper 20
[3] A. H. Gnauck, G. Raybon, S. Chandrasekhar, J. Leuthold, C. Doerr, L. Stulz, and E. Burrows,“25 × 40-Gb/s copolarized DPSK transmission over 12 × 100-km NZDF with 50-GHz channel
spacing,” Photonics Technol. Lett., vol. 15, pp. 467–469, 2003.
[4] N. Yoshikane and I. Morita, “1.14 b/s/Hz spectrally efficient 50 × 85.4 Gb/s transmission
over 300 km using copolarized RZ-DQPSK signals,” J. Lightw. Technol., vol. 23, no. 1, pp.
108–114, Jan. 2005.
[5] A. H. Gnauck, P. J.Winzer, S. Chandrasekher, and C. Dorrer, “Spectrally efficient (0.8b/s/Hz) 1-Tb/s (25 × 42.7 Gb/s) RZ-DQPSK transmission over 28 100-km SSMF spans with 7
optical add/drops,” presented at the ECOC 2004, Postdeadline Paper Th4.4.1.
[6] R. A. Griffin, “Integrated DQPSK transmitters,” presented at the OFC 2005, Paper OTuM1.
[7] K. Ishida, K. Shimizu, T. Mizuochi, K. Motoshima, D. S. Ly-Gagnon, and K. Kikuchi,“Transmission of 20 × 20 Gb/s RZ-DQPSK signals over 5090 km with 0.53 b/s/Hz spectral
efficiency,” presented at the OFC 2004, Paper FM2.
[8] N. Kikuchi, S. Sasaki, K. Sekine, and T. Sugawara, “Investigation of cross phase modulation(XPM) effect on amplitude- and phase-modulated multi-level signals in dense-WDM
transmission,” presented at the OFC 2005, Paper OWA4.
[9] T. Miyazaki, Y. Awaji, Y. Kamio, and F. Kubota, “Field demonstration of 160-Gb/s OTDM
signals using eight 20-Gb/s 2-bit/symbol channels over 200 Km,” presented at the OFC 2005,
Paper OFF1.
[10] W. Idler, A. Klekamp, R. Dischler, and B. Wedding, “Advantages of frequency shift keying
in 10-Gb/s systems,” presented at the 2004 IEEE/LEOS Workshop on Advanced Modulation
Formats, Paper FD3.
[11] T. Kawanishi, T. Sakamoto, S. Shinada, M. Izutsu, K. Higuma, T. Fujita, and J. Ichikawa,17/32“LiNbO3 high-speed optical FSK modulator,” Electron. Lett., vol. 40, pp. 691–692, 2004.
[12] T. Kawanishi, T. Sakamoto, S. Shinada, M. Izutsu, K. Higuma, T. Fujita, and J. Ichikawa,“High-speed optical FSK modulator for optical packet labeling,” J. Lightw. Technol., vol. 23, no.
1, pp. 87–94, Jan. 2005.
[13] T. Sakamoto, T. Kawanishi, T. Miyazaki, and M. Izutsu, “Novel modulation scheme for
optical continuous-phase frequency-shift keying,” presented at the OFC 2005, Paper OFG2.
[14] T. Sakamoto, T. Kawanishi, and M. Izutsu, “Optical minimum-shiftkeying with external
modulation scheme,” Opt. Exp., vol. 13, pp. 7741– 7747, 2005.
[15] M. Izutsu, S. Shikamura, and T. Sueta, “Integrated optical SSB modulator/frequency
shifter,” J. Quantum Electron., vol. 17, pp. 2225–2227, 1981.
[16] T. Kawanishi and M. Izutsu, “Linear single-sideband modulation for high- SNR
wavelength conversion,” Photon. Technol. Lett., vol. 16, pp. 1534–1536, 2004.
[17] D. D. Fonseca, P. Monteiro, A. V. T. Cartaxo, and M. Fujita, “Single sideband
demonstration using a four phase-modulators structure,” presented at the 2004 IEEE/LEOS
Workshop on Advanced Modulation Formats, Paper FC2.
[18] J. J. Vegas Olmos, I. Tafur Monroy, and A. M. J. Koon, “High bit-rate combined FSK/IM
modulated optical signal generation by using GCSR tunable laser sources,” Opt. Exp., vol. 11,
pp. 3136–3140, 2003.
[19] K. Vlachos, J. Zhang, J. Cheyns, S. Nan Chi, E. Van Breusegem, I. Tafur Monroy, J. G. L.
Jennen, P. V. Holm-Nielsen, C. Peucheret, R. O’Dowd, P. Demeester, and A. M. J. Koonen, “An
optical IM/FSK coding technique for the implementation of a label-controlled arrayedwaveguide
packet router,” J. Lightw. Technol., vol. 21, no. 11, pp. 2617–2628, Nov. 2003.
[20] T. Sakamoto, A. Chiba and T. Kawanishi, “50-Gb/s 16 QAM by a quad-parallel MachZehnder modulator,” presented at the ECOC 2007, Postdeadline Paper 2.8[21] Christopher R. Doerr, P. J. Winzer, L. Zhang, L. Buhl and N. J. Sauer, “Monolithic 80-Gb/s
Dual-Polarization On-Off-Keying Modulator in InP,” presented at the OFC 2008, Postdeadline
Paper 19[22] T. Kawanishi, T. Sakamoto, A. Chiba and M. Izutsu, “Study of precise optical modulation
using Mach-Zehnder interferometers for advanced modulation formats,” presented at the ECOC
2007, 6.2.3,[23] T. Kawanishi, T. Sakamoto, A. Chiba, M. Izutsu1, P. J.Winzer, “Duobinary Signal
Generation Using High-Extinction Ratio Modulation,” presented at the OFC 2008, OWL2
D4. Photonic Signal Processing
The final target of photonic signal processing is to realize all optical switching and all optical
logical processing, and very wide range of topics are included. Recently, more sophisticatedsignal processing is enabled due to the appearance of high power optical sources and highnonlinearity media. The kinds of nonlinearity utilized are increasing and SHG (sum frequency
generation), DHG (difference frequency generation) and two photon absorption are also utilized
in addition to well-known XPM (cross phase modulation), FWM (four wave mixing), Raman
scattering and Brillouin scattering.
As for optical fiber signal processing, concerns on optical pulse compression with CPF(comb-like profiled fiber) and supercontinuum light generation with very wideband, stable andexcellent frequency characteristics are increasing. On wavelength conversion, many new
schemes with superior performance are proposed, using HNLF (high nonlinearity fiber) andSOA (semiconductor optical amplifier) that both of them are used in variation of configurationof MZI (Mach-Zehnder interferometer) and ring interferometer.
Optical functional devices are being advanced rapidly. For example, optical label
recognition of OCDMA (optical code division multiplexing) signal using SSFBG (super-18/32structured fiber Bragg grating) and optical logic device (bistable device, optical memory, opticalswitch, optical NOR gate, etc.) are included. The papers on all optical regeneration (2R and
3R) using these functional devices are often found.
K. Igarashi, H. Tobioka, M. Takahashi, J. Hiroishi, T. Yagi, M. Sakano and S. Namiki [2005],“Widely tunable sub-picosecond compression of 40 GHz externally-modulated pulse train using
1.4 km long comb-like profiled fiber”, OFC/NFOEC 2005, Optical Fiber Communication
Conference, JWA6
S. Oda and A. Maruta[2005], “All-optical analog-to-digital conversion by slicing
supercontinuum spectrum and switching with nonlinear optical loop mirror”, OFC/NFOEC
2005, Optical Fiber Communication Conference, OThN3
M. Naruse, T. Miyazaki, and F. Kubota, H. Yoshida and H. Ishikawa[2005], “Ultrafast alloptical NOR gate based on intersubband and interband modulation operating at communication
wavelengths”, OFC/NFOEC 2005, Optical Fiber Communication Conference, OFE3
J. Suzuki, T. Tanemura, K. Tara, Y. Ozeki, and K.Kikuchi[2005], “All-Optical Regenerator
Using Wavelength Shift Induced by Cross-Phase Modulation in Highly-Nonlinear
Fibers”,OFC/NFOEC 2005, Optical Fiber Communication Conference, OME64
H. Furukawa, N. Wada and T. Miyazaki [2005], “Demonstration of 160 Gbit/s Optical Packet
Switching and Buffering Based on All-optical Code Label Processing”, LEOS 2005, The 18th
Annual Meeting of the IEEE Lasers and Electro-Optics Society, pp.89-90
H. Nishioka, K. Hayasaka, H. Tomita, K. Ueda[2005], “Frequency-domain phase conjugator by
a two-photon gated Bragg grating for nJ laser pulses”, LEOS 2005, The 18th Annual Meeting of
the IEEE Lasers and Electro-Optics Society, pp.697-698
M. Matsuura, N. Kishi, and T. Miki[2006], “Ultra-Wideband Wavelength Conversion over 300
nm by Cascaded SOA-Based Wavelength Converters”, OFC/NFOEC 2006, Optical Fiber
Communication Conference, PDP29
M. Hattori, K. Nishimura, R. Inohara and M. Usami[2006], “New operation scheme of SOAMZI all-optical wavelength converter cancelling cross gain modulation”, OFC/NFOEC 2006,
Optical Fiber Communication Conference, OWS5
J. Kurumida, H. Uenohara, and K. Kobayashi[2006], “All-optical Label Recognition with SOAMZI Multistage Switching Scheme”, OFC/NFOEC 2006, Optical Fiber Communication
Conference, JThB51
T. Hamanaka, X. Wang, N. Wada and K. Kitayama[2006], “511-chip SSFBG and DFG-based
optical thresholder enabled compound data rate (10Gbps-622Mbps) OCDMA experiment for
multiple service provisioning platform”, OFC/NFOEC 2006, Optical Fiber Communication
Conference, OThT4
K. Takiguchi, H. Takahashi, and O. Moriwaki and M. Okuno[2007], “Integrated photonic
decoder with complementary code processing and balanced detection for two-dimensional
OCDMA”, OFC/NFOEC 2007, Optical Fiber Communication Conference, OWV5
H. Furukawa, A. Nirmalathas, N. Wada, S. Shinada, H. Tsuboya, and T. Miyazaki[2007],19/32“All Optical Tunable Wavelength Conversion at > 160 Gb/s” , OFC/NFOEC 2007, OpticalFiber Communication Conference, OTuI1
K. Iwashita and K. Nakajima[2007], “Digitally Tunable Optical Frequency Converter based on
Optical SSB Modulators and Mach-Zehnder”, OFC/NFOEC 2007, Optical Fiber
Communication Conference, JWA56
H. Tamai, M. Sarashina, K. Sasaki, and M. Kashima[2007], “First Demonstration of Clockless
Serial Optical Code Label Switching with SSFBGs Label Recognizer”, OFC/NFOEC 2006,
Optical Fiber Communication Conference, JThA72
K. Takano, N. Hanzawa, S. Tanji, and K. Nakagawa[2007], “Experimental Demonstration of
Optically Phase-Shifted SSB Modulation with Fiber-Based Optical Hilbert Transformers”,
OFC/NFOEC 2007, Optical Fiber Communication Conference, JThA84
T. Sakamoto, T. Kawanishi and M. Izutsu[2007], “Optimization of Electro-Optic Comb
Generation Using Conventional Mach-Zehnder Modulator”, MWP 2007, IEEE International
Topical Meeting on Microwave Photonics, pp.50-53
M. Takenaka, K. Takeda, Y. Kanema, M. Raburn, T. Miyahara, H. Uetsuka and Y. Nakano[2007],“MMI bistable laser diode optical flip-flops for all-optical packet switching networks”, LEOS
2007, The 20th Annual Meeting of the IEEE Lasers and Electro-Optics Society, pp.652-653
G. Hirano and F. Koyama[2007], “Slowing Light in Bragg Reflector Waveguide with Tilt
Coupling Scheme”, LEOS 2007, The 20th Annual Meeting of the IEEE Lasers and ElectroOptics Society, pp.86-87
D5. THz Technology
Terahertz (THz) electromagnetic waves, which cover an unexplored portion of spectrum
between infrared and microwaves at frequencies from 100 GHz to 10 THz, have been expected
to offer innovations in sensing, imaging, spectroscopy, and communications. In Japan, several
organizations, which contribute to accelerate the THz science and technology in both academic
societies and industries, have been established; Terahertz Technology Forum, Technical Groupon Terahertz Application Systems in the Institute of Electronics, Information andCommunication Engineers (IEICE), Terahertz Technology Professional Group in the Japan
Society of Applied Physics (JSAP), Technical Group on Terahertz Electromagnetic-wave
Industrial Applications in Japan Science and Technology Agency (JST), Division of Terahertz
Spectroscopy in Spectroscopical Society of Japan, etc.
Generation of high power THz signals is the most important for the continuing advance ofTHz technology. Photonic generation of THz signals based on photomixing in nonlinear optical(NLO) crystals and photodiodes has been studied in the continuous-wave (CW) as well as
pulsed operations. Using an organic NLO crystal, DAST (4-dimethylamino-N-methyl-4
stilbazolium tosylate), Suizu et al. succeeded in the generation of high power THz waves up to
mid-IR range. Ito et al. reported CW generation of 10 microwatts power at 1 THz using anantenna-integrated uni-traveling-carrier photodiode (UTC-PD), which is the highest everobtained with photodiodes. Purely electronic devices have been examined with a resonant
tunneling diode (RTD) by Asada et al., and a Bloch oscillation by Hirakawa et al. A novel THz
emitter based on plasma-waves has been developed by Otsuji et al. A terahertz quantum cascadelaser (QCL) technology led by Hosako et al. is an alternative promising approach, though a lowtemperature operation is required. As for THz-signal detection technologies, Komiyama et al.

20/32developed a highly-sensitive THz detector, or a single photon counter based on quantum dots.
In recent years, there have been increasing research and development on real-world
applications of the THz technology. They include measurement and sensing systems, such as
real-time THz spectrometer (Guo et al.), real-time 2D imaging (Hattori et al.), detection of
crystalline defects (Nishizawa et al.), detection of illicit drugs in mail (Dobroiu et al.), detectionof inflammable liquids (Ikeda et al.), gas sensing (Song et al.), detection of protein (Yoshida etal.), diagnostics of cancer tissues (Nakajima et al.), THz spectroscopy in water and biologicalsolution (Nagai et al.), compact sensor chips for THz spectrometer (Kitagawa et al.), LSI testing(Yamashita et al), measurement of paint film thickness (Yasuda et al.), etc.
There is an urgent demand for higher data rate in wireless access systems in order to keep up
with the remarkable speed-up of fiber-optic networks. 10-Gbit/s data rate is now required for thewireless transmission of 10-Gigabit Ethernet (10GbE) signals, and multiplexed transmission of
uncompressed high-definition television (HDTV) signals. NTT has demonstrated the highest
data rate of 10 Gbit/s using 120-GHz and 240-GHz carrier frequencies. Use of higher
frequencies of over 300 GHz is one of the trends from now on as the IEEE 802.15 Terahertz
Interest Group was launched in late 2007.
References
Asada, M., N. Orihashi, and S. Suzuki [2007], “Voltage-controlled harmonic oscillation at about
1 THz in resonant tunneling diodes integrated with slot antennas”, Jap. J. Appl. Phys., vol. 46,
no. 5A, pp. 2904-2906
Dobroiu, A., Y. Sasaki, T. Shibuya, C. Otani, and K. Kawase [2007], “THz-wave spectroscopy
applied to the detection of illicit drugs in mail”, Proc. IEEE, vol. 95, no. 8, pp. 1566-1575
Guo, R., H. Minamide, T. Ikari, Y. Ishikawa, and H. Ito [2006], “Terahertz-wave spectrometerbased on a coherent terahertz-wave parametric generator”, Opt. Eng. vol. 45, pp113603
Hashiba, H., and V. Antonov,L. Kulik,A. Tzalenchuk, P. Kleinschmid, S. Giblin, and S.
Komiyama [2006], “Isolated quantum dot in application to terahertz photon counting”, Phys.
Rev. B, vol. 73, 081310
Hattori, T., K. Egawa, S. Ookuma, and T. Itatani [2006], “Intense terahertz pulses from largeaperture antenna with interdigitated electrodes,” Jpn. J. Appl. Phys., vol. 45, no. 15, pp. L422L424
Hattori, T. and M. Sakamoto [2007], “Deformation corrected real-time terahertz imaging,” Appl.
Phys. Lett., vol. 90, no. 26, 261106
Hirata, A., T. Kosugi, H. Takahashi, R. Yamaguchi, F. Nakajima, T. Furuta, H. Ito, H. Sugahara,
Y. Sato, and T. Nagatsuma [2006], “120-GHz-band millimeter-wave photonic wireless link for
10-Gb/s data transmission”, IEEE Trans. Microwave Theory Tech., vol. 54, no. 5, pp.1937-1944
Hosako, I., N. Sekine, M. Patrashin, S. Saito, K. Fukunaga, Y. Kasai, P. Baron, T. Seta, J.
Mendrok, S. Ochiai, and H. Yasuda [2007], “At the dawn of a new era in terahertz technology”,
Proc. IEEE, vol. 95, no. 8, pp. 1611-1623
Ikeda, T., A. Matsushita, M. Tatsuno, Y. Minami, M. Yamaguchi, K. Yamamoto, M. Tani, and M.
Hangyo [2005], “Investigation of inflammable liquids by terahertz spectroscopy”, Appl. Phys.
Lett., vol. 87, no. 3, 034105

21/32

Ito, H., F. Nakajima, T. Furuta, T. Ishibashi [2005], “Continuous THz-wave generation using
antenna-integrated uni-travelling-carrier photodiodes”, Semicond. Sci. Technol., vol. 20, no. 7
pp. S191-S198
Kitagawa, J., T. Ohkubo, M. Onuma, and Y. Kadoya [2006], “THz spectroscopic
characterization of biomolecule/water systems by compact sensor chips”, Appl. Phys. Lett., vol.
89, no. 4, 041114
Miyamaru, F., M. Takeda, T. Suzuki, and C. Otani [2007], “Highly sensitive surface plasmon
terahertz imaging with planar plasmonic crystals”, Optics Express, vol. 15, no. 22 pp. 1480414809
Nagai, M., H. Yada, T. Arikawa, and K. Tanaka [2006], “Terahertz time-domain attenuated totalreflection spectroscopy in water and biological solution”, International Journal of Infrared andMillimeter Waves, vol. 27, no. 4, pp. 505-515
Nagatsuma, T. [2006], “Exploring sub-terahertz waves for future wireless communications”,
International Conference on Infrared and Millimeter-waves/Terahertz Electronics (IRMMWTHz2006), PL-4, p. 4
Nagatsuma, T., H. Ito, and T. Ishibashi [2007], “Photonic THz sources using uni-travelingcarrier photodiode technologies”, Tech. Dig. IEEE LEOS Annual Meeting, ThN3, Florida, pp.
792-793
Nagatsuma, T., A. Hirata, N. Kukutsu, and Y. Kado [2007], “Multiplexed transmission of
uncompressed HDTV signals using 120-GHz-band millimeter-wave wireless link”, IEEE Intern.
Meeting on Microwave Photonics, MWP 2007, pp. 237-240
Nagatsuma, T. and Y. Kado [2007], “Microwave and millimeter-wave photonic devices forcommunications and measurement applications”, Asia Optical Fiber Communication and
Optoelectronics Conference, AOE 2007, pp. 63-65
Nakajima, S., H. Hoshina, M. Yamashita, C. Otani, and N. Miyoshi [2007], “Terahertz imaging
diagnostics of the cancer tissues with Chemometrics technique” Appl. Phys. Lett., vol. 90, no. 4,041102
Nishizawa, J. T. Sasaki, K. Suto, T. Yamada, T. Tanabe, T. Tanno, T. Sawai, Y. Miura [2005],“THz imaging of nucleobases and cancerous tissue using a GaP THz-wave generator”, Opt.
Comm., vol. 244, no. 1-6, pp. 469-474
Nishizawa, J., K. Suto, T. Sasaki, T. Tanabe, T. Tanno, Y. Oyama, F. Sato [2006], “GaP Raman
terahertz high accuracy spectrometer and its application to detect organic and inorganic
crystalline defects”, Proceedings of the Japan Academy, Ser. B, vol. 82, no. 9, pp. 353-358
Otsuji, T., M. Hanabe, T. Nishimura [2006], “A grating-bicoupled plasma-wave photomixer
with resonant-cavity enhanced structure”, Optics Express, vol. 14, no.11, pp. 4815-4825
Song, Ho-Jin, N. Shimizu, T. Furuta, K. Suizu, H. Ito, and T. Nagatsuma [2007], “Broadband
frequency tunable photonic sub-terahertz wave generation for spectroscopic applications” Tech.
Dig. IEEE LEOS Annual Meeting, ThF2, pp. 733-734

22/32

Suizu, K., K. Miyamoto, T. Yamashita, and H. Ito [2007], “High-power terahertz-wave
generation using DAST crystal and detection using mid-infrared powermeter”, Opt. Lett., vol.32,
no.19, pp. 2885-2887
Syouji, A., S. Saito, K. Sakai, M. Nagai, K. Tanaka, H. Ohtake, T. Bessho, T. Sugiura, T.
Hirosumi, and M. Yoshida [2007], “Evaluation of a terahertz wave spectrum and construction ofa terahertz wave-sensing system using a Yb-doped fiber laser”, J. Opt. Soc. Am., vol. B 24, no.
8, pp. 2006-2012
Tonouchi, M. [2007], “Cutting-edge terahertz technology”, Nature Photonics, vol. 1, no.2, pp.
97-105
Ueno, Y., R. Rungsawang, I. Tomita, and K. Ajito [2006], “Quantitative measurements of aminoacids by terahertz time-domain transmission spectroscopy,” Anal. Chem., vol. 78, no. 15, pp.
5424-5428
Unuma, T., N. Sekine, and K. Hirakawa [2006], “Dephasing of Bloch oscillating electrons in
GaAs-based superlattices due to interface roughness scattering”, Appl. Phys. Lett. vol. 89, no.
16, 161913
Yamashita, M., K. Kawase, C. Otani, T. Kiwa, M. Tonouchi [2005], “Imaging of large-scale
integrated circuits using laser terahertz emission microcopy”, Optics Express, vol. 13, no. 1, pp.
115-120
Yasuda, T., T. Iwata, T. Araki, and T. Yasui [2007], “Improvement of minimum paint film
thickness for THz paintmeters by multiple regression analysis”, Appl. Opt., vol. 46, no. 30, pp.
7518-7526
Yoshida, H., Y. Ogawa, Y. Kawai, S. Hayashi, A. Hayashi, C. Otani, E. Kato, F. Miyamaru, and
K. Kawase [2007], “Terahertz sensing method for protein detection using a thin metallic mesh”,
Appl. Phys. Lett., vol. 91, no. 25, 253901

D6. Silicon Devices
Device scaling of Silicon CMOS technology has enabled not only higher speed logic circuits
but also higher frequency analog/microwave circuits. As shown in Fig. 1, high frequency
performance of typical NMOS transistors in 65 nm technology node reaches their cutoff
frequency fT and maximum oscillation frequency fmax of over 200 GHz. The device scaling
supported by wide variety techniques, such as high-k dielectric gate insulator, low-k
interconnect insulator and thick Cu interconnect metal layer, enables also high Q passive
elements. In addition, Si CMOS technology, as well known, has specific features of lower
power consumption suitable to battery-driven mobile devices, higher level integration of RF
frontend and baseband circuits, and lower fabrication cost in mass production, compared to the
III-V compound semiconductor (GaAs, InP) technology.
These high performance Si CMOS analog/microwave circuits has started to prevail as RF
frontend ICs in several GHz frequency range applications, such as wireless local network(WLAN; IEEE 802.11a/b/g/n), 2G/3G cellar networks, worldwide interoperability for
microwave access (WiMAX; IEEE 802.16e), ultra-wideband impulse radio system (UWB-IR),and electronic toll collection system (ETC). Many types of RF CMOS ICs [1-8] have been

23/32developed such as low-noise amplifiers, voltage controlled oscillators (VCO), up/down
conversion mixers, power amplifiers, and multi-band multi-mode transceiver ICs.
Recently millimeter wave applications have much attention such as wireless personal area
network (IEEE 802.15.3c) and wireless high-definition signal transmission system (WirelessHD) in 60 GHz frequency range, and the vehicle radars including the short range radars andlong range radars for collision avoidance systems. The millimeter wave is ideal for short-range
high-capacity data transmission systems, as well as for measuring with high resolution andaccuracy the distance between two points. Conventionally, the compound semiconductors havebeen used in the RF front-end circuits of these systems in order to realize high gain, low noiseand high output power of high-frequency signals.
On the other hand, remarkable progress in Si CMOS technology, besides SiGe:C BiCMOS[12-16], has been made in regard to operational speeds and it is now possible to apply
millimeter wave circuits that were previously achieved through compound semiconductors.
Practical application, however, of Si CMOS technology in millimeter-wave circuitry has been
problematic due to the occurrence of significant signal loss due to the conductive Si substrateand lack of an accurate device model up to millimeter wave frequency range. Among
millimeter-wave circuitry, power amplifiers and VCO are key circuit blocks. As shown in Fig. 2,
power amplifier is one of the toughest targets due to the low-breakdown voltage of nm-scaled Si
CMOS transistors. In VCO its frequency tuning range is significantly narrowed by the reduced
ratio between the tuning varactor diode to parasitic capacitance in the scaled devices. There
were several reports relating to technological challenges to overcome these problems [9-11].
Furthermore, by combining baseband circuit with RF front-end circuit on one chip, millimeterwave band transceiver chips - which had been expensive to produce in the past - can now be
made considerably smaller. As a result, widespread applications of millimeter wave Si CMOS
technology in both automotive radar systems and wireless communications systems are
anticipated in the future.

Fig.
Fig. 2

Output power of CMOS power amplifiers

Reference:
Si CMOS1

TrendsoffT and fmax

24/32[1] T. Maeda, N. Matsuno, S. Hori, T. Yamase, T. Tokairin, K. Yanagisawa, H. Yano, R.
Walkington, K. Numata, N. Yoshida, Y. Takahashi, and H. Hida [2006], “A Low-Power DualBand Triple-Mode WLAN CMOS Transceiver,” IEEE Journal of Solid-State Circuits, vol. 41,
pp. 2481–2490.
[2] T. Maeda, H. Yano, S. Hori, N. Matsuno, T. Yamase, T. Tokairin, R. Walkington, N. Yoshida,
K. Numata, K. Yanagisawa, Y. Takahashi, M. Fujii, and H. Hida [2006], “Low-powerconsumption direct-conversion CMOS transceiver for multi-standard 5-GHz wireless LAN
systems with channel bandwidths of 5-20 MHz,” IEEE J. of Solid-State Circuits, vol. 41,
pp.375–383.
[3] K. Yanagisawa, N. Matsuno, T. Maeda, and S. Tanaka [2007], “A New DC-Offset and I/QMismatch Compensation Technique for a CMOS Direct-Conversion WLAN Transmitter,”IEEE/MTT-S International Microwave Symp., pp. 85–88.
[4] R. Tachibana, S. Kousai, T. Kato, H. Kobayashi, R. Ito, A. Maki, D. Miyashita, Y. Araki, T.
Hashimoto, H. Hoshino, T. Sekiguchi, M. Ashida, I. Seto, M. Hamada, R. Fujimoto, H. Yoshida,
S. Otaka, [2007], “A 0.13 m CMOS 5GHz Fully Integrated 2x3 MIMO Transceiver IC withover 40dB Isolation” IEEE Radio Frequency Integrated Circuits (RFIC) Symposium, pp. 661–
664.
[5] T. Terada, R. Fujiwara, G. Ono, T. Norimatsu, T. Nakagawa, K. Mizugaki, M. Miyazaki, K.
Suzuki, K. Yano, A. Maeki, Y. Ogata, S. Kobayashi, N. Koshizuka, K. Sakamura, [2007], “A
CMOS UWB-IR Receiver Analog Front End with Intermittent Operation,” IEEE Symposium on
VLSI Circuits, pp. 86 – 87.
[6] T. Norimatsu, R. Fujiwara, M. Kokubo, M. Miyazaki, A. Maeki, Y. Ogata, S. Kobayashi, N.
Koshizuka, K. Sakamura, [2007], “A UWB-IR Transmitter With Digitally Controlled Pulse
Generator,” IEEE J. of Solid-State Circuits, vol. 42, pp. 1300 – 1309.
[7] T. Terada, S. Yoshizumi, M. Muqsith, Y. Sanada, T. Kuroda, [2006], “A CMOS ultrawideband impulse radio transceiver for 1-Mb/s data communications and ±2.5-cm range
finding,” IEEE Journal of Solid-State Circuits, vol. 41, pp. 891 – 898.
[8] H. Sugawara, Y. Yoshihara, K. Okada, K. Masu, [2005],“Reconfigurable CMOS LNA for
software defined radio using variable inductor,” The European Conference on Wireless
Technology, pp. 547 - 550.
[9] Y. Kawano, T. Suzuki, Y. Nakasha, T. Hirose, K. Joshin, [2007], “A 25-GHz, 40-mW FullyIntegrated Power Amplifier in Standard 90-nm Si-CMOS Technology,” Korea-Japan Microwave
Conference, pp. 17 – 20.
[10] H. Shigematsu, T. Hirose, F. Brewer, and M. Rodwell, [2005], “Millimeter-wave CMOS
circuit design,” IEEE Trans. on Microwave Theory and Techniques, vol. 53, pp. 472 – 477.
[11] T. Mitomo, R. Fujimoto, N. Ono, R. Tachibana, H. Hoshino, Y. Yoshihara, Y. Tsutsumi, I.
Seto, [2007], “A 60-GHz CMOS Receiver with Frequency Synthesizer,” IEEE Symposium on
VLSI Circuits, pp. 172 – 173.
SiGe BiCMOS[12] T. Oka, M. Hirata, Y. Ishimaru, H. Kawamura, and K. Sakuno, [2006], “SiGe HBT Power
Amplifier with Distortion-Controllable Bias Circuit and Its Application to 802.11g WirelessLANs,” Proceedings of Asia-Pacific Microwave Conference, pp. 133 - 136.
[13] T. Nakamura, T. Masuda, N. Shiramizu, K. Washio, T. Kitamura, N. Hayashi, [2006], “A
Wide-tuning-range VCO with Small VCO-gain Fluctuation for Multi-band W-CDMA RFIC,”
Proceedings of the 32nd European Solid-State Circuits Conference, pp. 448 - 451.
[14] S. Shinjo, K. Tsutsumi, K. Nakajima, H. Ueda, K. Mori, M. Hieda, J. Koide, M. Inoue, N.
Suematsu, [2006], “5.8GHz ETC SiGe-MMIC Transceiver having Improved PA-VCO Isolation
with Thin Silicon Substrate,” IEEE MTT-S International Microwave Symposium Digest, pp.

25/322039 - 2042.
[15] K. Tsutsumi, M. Kagano, and N. Suematsu, [2006], “A Double Tuned Ku-Band SiGeMMIC VCO with Variable Feed-Back Capacitor,” Proceedings of Asia-Pacific Microwave
Conference, pp. 1127-1130.
[16] T. Nakamura, T. Masuda, K. Washio, H. Kondoh, [2007], “A Low-Phase-Noise Low-Power
27-GHz SiGe-VCO using Merged-Transformer Matching Circuit Technique,” IEEE Radio
Frequency Integrated Circuits (RFIC) Symposium, pp. 413 - 416.
D7. A brief view on the ultra wideband (UWB) status in Japan
This report summarizes current status of ultra wideband technologies in Japan, from theviewpoints of standardizations, regulations, and research and development (R&D) activities.
1. Standardizations
The Association of Radio Industries and Businesses (ARIB), Japan, published the ARIB STDT91 ver. 1.0 [1], a standard for ultra wideband (UWB) radio systems, in December 2006. This
standard mainly provides system requirements for UWB radio systems in order to be inoperation in Japan. No specifications are given on the physical (PHY) and media access control(MAC) layers for UWB radio systems.
Note: As standardization activities on UWB radio systems, IEEE P802 standard committee had
engaged on 15.3a, for high data-rate UWB radio systems, and 15.4a, for low data-rate systems.
Two technologies competed in the 15.3a. One is a direct sequence UWB (DS-UWB), which is asingle-carrier UWB system using a spread spectrum technology. Another one is a multiband
OFDM (MB-OFDM), which is a multi-carrier UWB system with 128 sub-carriers. The 15.3a
was finally broken up in January 2006 because none of the two technologies could win out.
However, the MB-OFDM was approved as ECMA-368 and 369 in December 2005. Later, it
was also published as ISO/IEC 26907 and 26908 in May 2007. The 15.4a, is an impulse-based
UWB radio system for low-rate wireless personal area networks. It was published as an official
standard of IEEE P802 in March 2007.
2) Regulations
Japanese regulations on the UWB radio systems were issued in August 2007. The permission
PSD is -41.3 dBm/MHz in EIRP over the frequency ranges of 3.4-4.8 GHz (low-band) and 7.2510.25 GHz (high-band). This is equal to the US regulation prescribed by FCC. However, UWB
radio systems operating in the low-band are required to be equiped with an interference
mitigation technique against other existing radio systems; while as a transition, interference
mitigation techniques are not required for 4.2-4.8GHz until the end of 2008. In the Japanese
regulations, a UWB radio system is required to has a data rate beyond 50 Mbps, and, aminimum bandwidth beyond 450 MHz at -10 dB from the peak signal level. The Japanese
regulations on UWB will be revised after three years since publication.
Note: In the US, FCC deregulated the use of UWB radio systems in February 2002. The
permission PSD is -41.3 dBm/MHz in EIRP over frequency range of 3.1-10.6 GHz. In theEurope, EC issued to open the use of UWB radio systems in February 2007. The EU regulation
permits the PSD radiation of -41.3dBm/MHz over the frequency bands of 3.4 - 4.8 GHz and 6.0- 8.5 GHz. However, UWB radio systems operating in the frequency band from 3.4 to 4.8 GHz
are required to be equipped with an interference mitigation technique, such as low duty cycling(LDC). The frequency range 4.2-4.8 GHz is available without any interference mitigation
techniques until the end of 2010.
3. Research and development (R&D) activities
The R&D activities in Japan mainly follow the progress of its standardizations and regulations.

26/32On UWB radio systems for wireless communications, the main focus goes to the MB-OFDM
systems since MB-OFDM has been promised as PHY and MAC technologies in Wireless USB
and Bluetooth 3.0. Current R&D activities on the MB-OFDM systems include CMOS
implementation for the high-band [2] and development of low-power consumption techniques[3, 4]. As new application areas, UWB technologies have been applied into automotive radars[5] and medical and healthcare field [6, 7].
References[1] http://www.arib.or.jp/english/html/overview/doc/5-STD-T91v1_0-E.pdf[2] A. Tanaka, H. Okada, H. Kodama, and H. Ishikawa, “A 1.1V 3.1-to-9.5GHz MB-OFDM
UWB Transceiver in 90nm CMOS,” IEEE ISSCC 2006, pp.398-407, Feb. 2006.
[3] T. Norimatsu, R. Fujiwara, M. Kokubo, M. Miyazaki,Y. Ookuma, M. Hayakawa, S.
Kobayashi, N. Koshizuka, and K. Sakamura, "A novel UWB impulse-radio transmitter with alldigitally-controlled pulse generator," Proceedings of ESSCIRC 2005, pp.267-270, Sept. 2005.
[4] S. Iida, K. Tanaka, H. Suzuki, N. Yoshikawa, N. Shoji, B. Griffiths, D. Mellor, F. Hayden, I.
Butler, J. Chatwin, "A 3.1 to 5 GHz CMOS DSSS UWB transceiver for WPANs," ISSCC 2005,
vol.1, pp.214-594, Feb. 2005.
[5] T. Teshirogi, M. Ejima, M. Uchino, S. Saito, T. Kawamura, Y. Arayashiki, Y. Sakamoto, T.
Yoshida, Y. Watanabe, and A. Ishida, "UWB automotive radar to mitigate impact on radio
services using restricted band," Proceedings of APMC 2005, vol. 1, Dec. 2005.
[6] K. Takizawa, H.-B. Li, and R. Kohno, ” Wireless Vital Sign Monitoring using Ultra
Wideband-Based Personal Area Networks,” IEEE EMBS 2007, pp. 1798-1801, Aug. 2007.
[7] J. Wang and D. Su, "Design of an Ultra Wideband System for In-Body WirelessCommunications," The 2006 4th Asia-Pacific Conference on Environmental Electromagnetics,
pp.565-568, Aug. 2006.

D8. Body Area Network Devices
Wireless body area network, BAN or WBAN, consists of a set of small intercommunicating
wireless device having compact sensors, either wearable or implanted into the human body,which can monitor vital information, body movement, etc. These devices transmit data from thebody to a base station, from where the data can be forwarded to a hospital, clinic, home, etc., inreal time. Currently BAN systems are actively being discussed at IEEE802.15.6 BAN
standardization group [1]. Besides this standardization activity, research and development on
BAN are widely done for realizing medical, health-care and entertainment applications having
the frequency range of 400 MHz (medical implanted communication system, MICS band) to
10.4 GHz (UWB band) [2]. Radio propagation analysis and modeling around a body is
continuously investigated by using FDTD method or real propagation measurements [4, 5]. Oneof the research topics needed to be addressed is that the BAN devices and its sensors used in
BAN have to be low on complexity, small in form factor, light in weight, power efficient, easy
to use and reconfigurable - especially for realizing a small and high-efficient antenna in Figure 1[6]. Considerable effort would be required to make BAN transmission secure and accurate. It
would have to be made sure that the patient’s data is only derived from each patient’s dedicated
BAN system and is not mixed up with other patient’s data. Furthermore, the data generated fromBAN should have secure and limited access. To realize this, an easily inconvertible andundecipherable device-chip structure is also investigated [3].

27/32

Figure 1 The implant’s antenna layout and its SAR distribution for designed
implanted antenna at frequency of 403 MHz (Ref. [6]).

References[1] B. Zhen, H. Li, R. Kohno, "IEEE Body Area Networks for Medical Applications," the 4thInternational Symposium on Wireless Personal Communication Systems (ISWCS), 16 Oct.
(2007)[2] K. Takizawa, H. Li, K. Hamaguchi, R. Kohno, "Wireless patient monitoring using
IEEE802.15.4a WPAN," International Conference on Ultrawideband (ICUWB), 24, Sep. (2007)[3] M. Kuroda, C. Li, R. Kohno, “A Study of Energy-Efficient Authentication for Biosensor
Nodes in Body Area Networks,” the 2nd International Symposium on Medical Information andCommunication Technology (ISMICT), 11-13 Dec. (2007)[4] J. Wang, Y. Nishikawa, "Characterization and Performance of High-Frequency Pulse
Transmission for Human Body Area Communications," IEICE Transactions on
Communications, Vol.E90-B, No.6, pp. 1344-1350, Jun. (2007)[5] H. Yamamoto, T. Kobayashi, "Measurements and Characterization of Ultra Wideband
Propagation Channels between a Base Station and On-Body Antennas", the 2nd International
Symposium on Medical Information and Communication Technology (ISMICT), 11-13 Dec.
(2007)[6] K. Y. Yazdandoost, R. Kohno, “An Antenna for Medical Implant Communications System,”the 37th European Microwave Conference (EuMC), pp.968-971, 8-12 Oct. (2007)

D9. Millimeter-Wave Antennas
The research and development on millimeter-wave applications are getting hot again in recent
years, particularly in the field of millimeter-wave wireless communication systems for highspeed data transmission, such as millimeter-wave wireless personal network (WPAN).
Millimeter-wave antenna is an indispensable device for such systems. Resent research
activities on millimeter-wave antennas in Japan can be mainly categorized as below.
High gain and efficiency antenna array using waveguide-fed slot antenna structures.
Compact and high gain/efficiency array antennas have been developed for millimeter-wave
wireless communications and radars for vehicles at the operating frequencies from quasimillimeter-wave to 60 GHz and 76-77 GHz bands.
Wideband and relatively high-gain planar antenna have been developed for quasi-millimeterwave ultra-wideband system and for millimeter-wave WPAN. The developed antennas are of aplanar/multilayered structure antenna and a unique feeding/radiating structure which realize avery compact, wide operating bandwidth and relatively high-gain (~10 dBi) antenna. A
configuration and primary performance of the developed antennas for 60GHz millimeter-wave
WPAN are shown below.

28/32

NRD (Non-Radiative Dielectric) waveguide antenna for millimeter-wave applications. NRD
antenna can have a low transmission loss and hence high radiation efficiency at 60 GHz 76-77
GHz bands. Works on integration of the NRD antenna with the direct oscillator, mixer andother millimeter-wave circuits, performing a simple millimeter-wave RF module, has been also
carried out.
Beamforming/beam-steering array antenna for millimeter-wave wireless communications andradars. The research and development are focused on 60 GHz and 76-77 GHz bands, using
switchable sector antenna or phased antenna array to realize the beamforming/beam-steering
performance required from the systems.
New antenna at millimeter-wave frequencies. New material or new mechanism, particularly
the use of metamatrial, has been studied to realize some antenna performances such as wide
beam steering.
Active antenna Integrated with recent Si or SiGe CMOS devices. With the increasing
operating frequency of the recent CMOS devices, researches on the integration of suchsemiconductor devices, including active circuits such as amplifier are paid attention fordeveloping future compact, efficient and easy-controlling antenna modules for the millimeterwave communication systems and radars.

29/321.8

2.1

substrateh2

Unit: mm

6

1.5

1.9

Upper substrate ( r = 2.17)

h1

1 1.4

1.3

h1 = 0.254, h2 = 0.254

0.5

Lower substrate ( r = 2.17)

radiating patch

ine

0.7
0.7
7

gl

driving patch

in
ed

subs

trate

p
tri

fe

s

cro

mi

e

lan

ou

subs

gr

trate

Fig. 1p
nd

Stacked patch antenna with two driving patches

015> 14 GHz
10

Antenna Gain (dBi)

Return Loss |S11| (dB)

-10

-20

-30

> 9 dBi
5

0

-40

-5
50

55

60

65

70

50

Frequency (GHz)(a)
Fig. 2

55

60

Frequency (GHz)(b)
Measured antenna performance: (a) Return loss and (b) Gain

EO sensing system
EO measurement
WaveguideProbe
EO imaging
Scanning
Image sensor

Fig. 3

Measured radiation patterns in H-plane of the developed antenna6530/32(at 58 GHz, 60 GHz, 63 GHz, and 65 GHz, respectively)

31/32

References[1] Yasuhiro TSUNEMITSU, Goro YOSHIDA, Naohisa GOTO, Jiro HIROKAWA, and Makoto
ANDO, "The Ridged Cross-Junction Multiple-way Power Divider for Small blockage andSymmetrical Slot Arrangement in the Center Feed Single-Layer Slotted Waveguide
Array,"IEICE Trans. Commun., Vol.E91-B, No.6, pp.-, Jun. 2008.
[2] Yasuhiro Tsunemitsu, Shigeru Matsumoto, Yasuhiro Kazama, Jiro Hirokawa , and Makoto
Ando, "Reduction of Aperture Blockage in the Center-Feed Alternating-Phase Fed Single-Layer
Slotted Waveguide Array Antenna by E- to Hplane Cross-Junction Power Dividers,"IEEETransaction AP, communication. (to be published)[3] Kaoru Sudo, Toru Oizumi, Jiro Hirokawa and Makoto Ando "Reduction of Azimuthal
Amplitude Ripple in the Rotating-Mode Feed to a Radial Waveguide by Using a Crossed DogBone Slot," IEEE Trans. Antennas Propagat., vol.55, no.9, pp.2618-2622, Sept. 2007.
[4] Takafumi KAI, Yusuke KATOU, Jiro HIROKAWA, Makoto ANDO, Hiroshi NAKANO, andYasutake HIRACHI, "A Coaxial Line to Post-Wall Waveguide Transition for a Cost-Effective
Transformer between a RF-Device and a Planar Slot-Array Antenna in 60-GHz Band," IEICE
Trans. Commun., Vol.E89-B, No.5, pp.1646-1653, May 2006.
[5] Se-Hyun Park, Yasuhiro Tsunemitsu, Jiro Hirokawa, and Makoto Ando, "Center feed single
layer slotted waveguide array," IEEE Trans. Antennas Propagat., Vol.54, No.5, pp.1474-1480,
May 2006.
[6] Y. Kimura, M. Takahashi, J. Hirokawa, M. Ando, and M. Haneishi, "An Alternating-Phase
Fed Single-Layer Slotted Waveguide Array in 76GHz Band and Its Sidelobe Suppression,"
IEICE Trans. Electron., Vol.E88-C, No.10, pp.1952-1960, Oct. 2005.
[7] Sehyun Park, Y. Okajima, J. Hirokawa, M. Ando, "A slotted post-wall waveguide array withinterdigital structure for 45-deg linear and dual polarization," IEEE Trans. Antennas Propag.,vol.53, no.9, pp.2865- 2871, Sept. 2005.
[8]Y. Kimura, Y. Miura, T. Shirosaki, T. Taniguchi, T. Kazama, J. Hirokawa, M. Ando, T.
Shirouzu, "A Low-Cost and Very Compact Wireless Terminal Integrated on the Back of a
Waveguide Planar Array for 26 GHz Band Fixed Wireless Access (FWA) Systems", IEEE Trans.
Antennas and Propag., vol.53, no.8, pt.1, pp.2456-2463, Aug. 2005.
[9] Takuichi HIRANO, Jiro HIROKAWA, and Makoto ANDO, "A Design of a Leaky
Waveguide Crossed-Slot Linear Array with a Matching Element by the Method of Momentswith Numerical-Eigenmode Basis Functions," IEICE Trans. Commun., Vol.E88-B, No.3,
pp.1219-1226, March 2005.
[10] Keren Li, Naoki Kajitani, Kenneth K. F. Tong, and Toshiaki Matsui, "Ultra-Wideband(UWB) Stacked Patch Antenna for Quasi-Millimeter-Wave Application," Proceeding of
MINT-MIS2007/TSMMW2007/Millilab Workshop, vol.1, no. S2-1, pp.123-126, Seoul, Korea,
February 26-27, 2007.
[11] Tomoaki Sato, Keren Li, Naoki Kajitani, Remi Roux, and Huan-Bang Li, "Wideband
Stacked Patch Antenna with Two Driving Patches for Millimeter-wave Application (inJapanese)," 2007 IEICE Electronics Society Symposium, B-1-2, pp. S-3, Sept. 2007.
[12] Keren Li, and Tomoaki Sato, "Wideband Planar Antennas for Millimeter-Wave WirelessCommunications," 2008 IEEE AP-S International Symposium on Antennas and Propagation and2008 USNC/URSI National Radio Science Meeting in San Diego, California, USA, on July 0512, 2008.
[13] T.Shimizu and T.Yoneyama, "NRD-Guide and Waveguide H-Plane Transition and Its
Application for Lens Antenna Feeding Structure," IEICE Trans. Electron., vol.J89-C, no.5,
pp.312-320, May. 2006.
[14] T.Shimizu and T.Yoneyama, "Feeding Structures for 60GHz Dielectric Lens Antenna with
Low Sidelobes," IEICE Trans. Electron., Vol.J88-C, No.12, pp.1096-1105, Dec. 2005.
[15] T.Shimizu, T.Yoneyama, "A NRD Guide Fed Dielectric Lens Antenna with High Gain and32/32Low Sidelobe Characteristics," IEICE Trans. Electron., Vol.E88-C, No. 7, pp.1385-1386, Jul.
2005.
[16] Akifumi Hirata, Eddy Taillefer, Hiroyoshi Yamada, and Takashi Ohira, "Handheld DOA
Finder with Electronically Steerable Parasitic Array Radiator Using the Reactance-Domain
MUSIC Algorithm," IEEE Proceedings Microwaves, Antennas & Propagation, 2007, 1, (4),pp.815-821, Aug. 2007.
[17] Qing Han, Nobuyuki Tenno, Amane Miura, Masazumi Ueba and Takashi Ohira, "Radial
Fed SP8T Varactor-Mounted Waveguide Switch for Millimeter-Wave Beam Steerable Antenna,"2007 IEEE AP-S International Symposium and USNC/URSI National Radio Science Meeting,pp.4377-4380, Jun. 2007.
[18] Qing Han, Nobuyuki Tenno, Amane Miura and Takashi Ohira, "Tapered Radial Fed Circuit
and Varactor-Mounted Waveguide Switch for Millimeter-Wave Switched Sector-BeamAntenna," International Workshop on Antenna Technology 2007_, pp.295-298, Mar. 2007.
[19] Nobuyuki Tenno, Amane Miura, Takashi Itoh, Makoto Taromaru and Takashi Ohira, "A
Fundamental Study on a Switched-beam Sector Slot-array Antenna in 60GHz Band," 2006
International Symposium on Antennas and Propagation, pp.1-5, Nov. 2006.
[20] Qing Han, Munehisa Yabuzaki, Makoto Taromaru, Takashi Ohira and Masami Akaike,"Radial Fed Circuit For Millimeter-Wave Switched Sector-Beam Antenna," 2006 IEEE AP-S
International Symposium and USNC/URSI National Radio Science Meeting , pp.3447-3450,
July 2006.
[21] S.-i. MATSUZAWA, K. SATO, A. SANADA, and H. KUBO, "Gain Improvement of a
Microstrip Composite Right/Left-Handed Leaky Wave Antenna Using Symmetrical Unit Cells
with Short Stubs," IEICE Trans B: Communications, E90-B(6): 1559 - 1561, June 1, 2007.
[22] Shin-ichiro Matsuzawa, Kazuo Sato, Yoshinori Inoe, Tsuyoshi Nomura, "Millimeter-Wave
Steerable Composite Right/Left-Handed Leaky Wave Antenna for Automotive Applications,"
IEICE Technical Report, vol. 106, no. 48, MW2006-24, pp. 69-72, May 2006.
[23] M. Sasaki, “Design of a Millimeter-Wave CMOS Radiation Oscillator With an Above-Chip
Patch Antenna,” IEEE Trans. Circuits Syst. II, Vol. 53, No.10, pp.1128-1132, 2006.