JAPANESE SITE REPORTS

Site: Advanced Telecommunications Research
Institute International (ATR)
ATR Optical and Radio Communications
Research Laboratory
2-2 Hikaridai
Seika-cho Soraku-gun
Kyoto 619-02, Japan

Date Visited: October 12, 1992

Report Author: P. Hager

ATTENDEES

NASA/NSF:

R. DePaula
P. Hager
R. Kwan
E. Miller

HOSTS:

Dr. Yoji Furuhama

President

Dr. Masayuki Fujise

Head, Radio Communications Department

BACKGROUND

The Advanced Telecommunications Research Institute International (ATR) was established in March 1986 with support from various sections of industry, academia and government and was intended to serve as a major center of basic and creative telecommunications R&D. Another of its functions is to establish research relationships both domestically and abroad. The present, new research laboratory was opened in the spring of 1989.

ATR is comprised of five laboratories:

The ATR R&D FY 1992 budget was 9 billion yen, approximately $75 million. ATR is supported by investments from 139 companies. ATR International has a capital investment of 22.01 billion yen, approximately $183 million. They have 200 people assigned to R&D, with approximately 40 people assigned to the Optical and Radio Communications Research Laboratories.

The ATR laboratories operate under four basic principles:

  1. Promotion of basic and creative telecommunications research
  2. Joint research opportunities for industrial, academic and government organizations
  3. Contributions to international society
  4. Future central role in Kansai Science City

The ATR laboratories are committed to publishing their results. Each researcher publishes about one paper per year in the international community and almost three papers each in the domestic community.

ATR laboratories have ultra modern facilities including an RF anechoic chamber, a clean room, a variable reverberation chamber, super mini-computers, parallel processing super mini-computers, and a conference room seating 228, with simultaneous interpretation and audio-visual facilities.

The Optical and Radio Communications Research Lab performs research and studies on technologies focused on 10-year horizon-to-fruition objectives.

See also the site report by V. Chan (Oct. 27 visit).

RESEARCH AND DEVELOPMENT ACTIVITIES

Key Technologies for Optical Intersatellite Communications

Optical Beam Control Technology. The panel was shown the ATR optical beam control laboratory equipment. The hardware was of high quality and design. The system used optical Fourier transform lenses made by Nikon to extend the optical transmission range to obtain a far-field test system configuration. The range was equipped with vacuum tubular chambers of two sections of approximately 17.5 meters each. The receiver sensor was a charge-coupled device (CCD) camera with lenses removed. Recordings of spacecraft vibrations obtained from ESA were being used to modulate/vibrate the optical fiber transmitter source for the range. This enabled the researchers to evaluate laser ISLs under realistic, space-based situations.

2.5 Gigabit Laserlink Capacity. ATR has developed a design for a 2.5 Gbits/sec laser ISL. Their design requires a high power ISL transmitter design to obtain high saturation output power, resulting in a reduced noise figure. ATR is experimenting with various stripe configurations; a tapered stripe and an SCH configuration have been applied to reduce the spontaneous emission and to lower the confinement factor. They have conducted laboratory experiments using a semiconductor laser amplifier which they developed. The experiments involve the use of multi-mode fiber in conjunction with experiment observations (Nohara and Fujise 1992). PSK coherent modulation was being investigated. No laboratory experiments in progress were observed.

ATR has researched optical modems for optical ISLs. Calculated results were verified with experiments using commercially available laser diodes. Laser diodes with an average power of 100 mW were modulated at 360 Mbits/sec.

Advanced Array Antennas. Active array antennas fabricated at the facility were displayed. The research objective is to achieve active arrays that are small and inexpensive for use in mobile satellite communications. The antennas shown included planar arrays of 16 elements and phased arrays formed on spherical sections. (Some arrays were implemented with 19 elements.) Research included work to determine and optimize range of elevation angle tracking and beam form control with minimized sidelobes. A self-diplexing 4 x 4 (16 element) planar array was also displayed. ATR is investigating slot-coupled, microstrip antennas (Takeuchi, Chujo and Fujise 1992).

ATR has a microwave anechoic chamber measuring 25 x 44 x 12 m, operating over a frequency range of 500 MHz to 40 GHz. Measurements were demonstrated using an L-band planar array.

Key Technologies for Future Mobile Communications

RF Technology for Overcoming Multipath Propagation. A briefing was given on ATR's digital beam forming research, which was based on DSP technology. ATR is researching a non-linear equalizer using neural network technology for digital radio transmission channels. The bit error rate (BER) using this equalizer is lower than that of a conventional equalizer using a linear transferal filter.

MMIC Technologies Such as a Line-Unified FET, Multi-Layer MMIC and Multi-Active-Layer MMICs. "Dick Tracy"-size radio devices are being pursued using MMIC technology (Kamitsuna 1992; Banba et al. 1992; Kamitsuna et al. 1992; Takenaka et al. 1992; Ogawa et al. 1991; Hasegawa et al. 1992; Banba et al. 1991). ATR's MMIC work is also focused on an optical MMIC for transformation of optical to mm waves. It is one of the key devices for optical fiber/mm wave links for future personal communications.

Optical and Electronic Devices

ATR is investigating growth and characterization of semiconductors with precisely controlled atomic configurations, non-linear optical devices using semiconductor superlattices, and theoretical analysis of devices with new functions.

SUMMARY

ATR is a relatively young laboratory (1986). It has excellent facilities to support the research which has been started. The laboratory has initiated research in many areas essential to advanced telecommunications satellite development. They have a highly qualified staff. Their work in ISL pointing, active phased-array antennas, and MMIC devices is showing good results and promises significant technological advances.


Published: July 1993; WTEC Hyper-Librarian