Koji Yasukawa

A novel nonlinear distortion suppression method in RoF systems using optical filter

Convergence of communication and broadcasting which makes use of radio over fiber (RoF) network has been investigated. In RoF networks, although system costs can be reduced by employing sub-carrier multiplexing (SCM), it has issue that influence of nonlinear distortion becomes large. To overcome this issue, a novel method through which nonlinearity of EAM is canceled by optical filter whose output varied with optical wavelength is proposed in this paper. Results of nonlinear distortion suppression based on theoretical analysis are shown.

Broadband wireless-over-fiber technologies for integrated services of communications and broadcasting

Digital broadcasting service and variety of communication services, 4th generation mobile, broadband wireless-LAN etc. are developed recently. Broadband wireless service over fiber technologies may play an essential role for emerging integrated services of broadcasting and communications in the area of entrance network. Low-distortion transmission of broadband radio signals are developed as a collaborative work of Osaka University, Advanced Telecommunication research Institute (ATR) and Osaka Institute of Technology supported by Strategic Information and Communication R&D Promotion Program (SCOPE) of Government.

The convergence of broadcasting and heterogeneous wireless communications over fiber network — An experiment of field trial

This paper describes on application of Radio-on-Fiber, for the digital divide solution by utilizing CATV optical fiber network. We have been demonstrated RoF repeater system for heterogeneous wireless infrastructure by using indoor experiment, however field trial is required. Now, the radiation inspection have been done as an experiment bureau in the mountainous area at the Nosegawa village in Nara prefecture, Japan aiming evaluating the correspondence with the link budget design, and clarifying wireless coverage of the proposed system. In this paper, the SCM RoF transmission of multiple radio services and result of the field trial is reported.

Design of compact transceiver optical systems for optical intersatellite links

In optical communication links between GEO satellites, all optical beam control functions required for the transceiver may be realized without using external gimbals. Configuration of such a transceiver internal optical system can be designed considering the satellite dynamics in orbit. This paper presents a design of the transceiver internal optical systems, taking into account the accuracy of satellite station-keeping and attitude control as well as an orbital separation. An experimental optics was constructed on the basis of the results for a bidirectional link between satellites separated by about 60 deg in orbit. The attitude control accuracy of + or - 0.1 deg and the satellite station-keeping of + or - 0.1 deg were assumed. It can be utilized to develop a variety of beam-controlling schemes.

Performance analysis of IM/DD radio-on-fiber link for transmitting multicarrier RF signals

Nowadays, the RoF technology can utilize to converge the broadcasting and the broadband wireless communications, because of their huge bandwidth, and protocol transparency. Transmitting RF signals are deteriorated by the nonlinearity of the RoF link and following RF amplifier. This paper provides analysis method of intermodulation distortion and peak factor of multicarrier RF signals including IEEE802.11g, ISDB-T and IEEE802.16e-2005 over intensity modulation / direct detection (IM/DD) RoF link. Experimental evaluation is also presented in terms of the error vector magnitude (EVM).

Radio on Fiber (RoF) Project in Strategic Information and Communications R&D Promotion Program

Broadband wireless service over fiber technologies may play an essential role for emerging integrated services of broadcasting and communications in the area of entrance network. Purpose and major results of radio-on-fiber (RoF) project as a collaborative work of Osaka University, Advanced Telecommunication research Institute (ATR) and Osaka Institute of Technology supported by Strategic Information and Communication R&D Promotion Program (SCOPE) of Government are introduced.