Ryoji Takeyari

1.244-Gb/s 32-channel transmission using a shelf-mounted continuous-phase FSK optical heterodyne system

A total capacity of 40 Gb/s is achieved using a shelf-mounted continuous-phase frequency-shift-keying (CPFSK) optical heterodyne frequency-division-multiplexing (FDM) transmission system with 32 optical channels and a bit-rate of 1.244-Gb/s per channel. For achieving a stable bit-error-rate (BER) characteristics with high-sensitivity, narrow-linewidth laser diodes, a channel-spacing stabilization circuit, and an optical tuner are developed. The obtained sensitivity at a BER of 10/sup -9/ for fiber transmission over 121 km ranges from -45.1 to -44.2 dBm, which is 9.8-10.7 dB lower than the shot-noise-limited sensitivity. The crosstalk penalty is suppressed to within 0.1 dB. The developed system has feasibility achieving a distribution system which can distribute more than 250 HDTV (high definition television) signals or 1250 current-standard TV signals to about 8000 subscribers 10 km from the office, or a 40-Gb/s trunk-line system with a fiber span of more than 50 km. >

Alternate-mark-inversion optical continuous phase FSK heterodyne transmission using delay-line demodulation

Alternate-mark-inversion (AMI) optical continuous phase (CP) frequency-shift keying (FSK) heterodyne transmission using delay-line demodulation which has a higher receiver sensitivity compared to the transmission using single-filter demodulation has been achieved. Since the proposed delay-line demodulation method directly converts the received AMI-CPFSK signal into the nonreturn to zero (NRZ) baseband signal without the use of an AMI decoder, a heterodyne receiver with the same configuration as the conventional CPFSK transmission system is realized, even though AMI line coding is applied to the system. Transmission experiments at 622 Mb/s have been demonstrated for both pseudorandom 2/sup 7/-1 and 2/sup 23/-1-b patterns at the same receiver sensitivity of -41.1 dBm (the PD input power). >

Fully monolithically integrated 40-Gbit/s transmitter and receiver

40-Gbit/s ETDM transmitter and receiver, both with a 10-Gbit/s interface have been developed. All ICs used in the transmitter and receiver are integrated monolithically by using InP HBTs and SiGe HBTs.

Next-generation hybrid design of optoelectronic components with electronic components based on InP and related materials

A hybrid-design 40-Gbit/s optical transmitter was designed by using an emitter-follower driving circuit to reduce the modulating voltage and capacitance of an optical modulator. This design significantly reduces the power consumption to 0.8 W.

50-Gbit/s AGC and modulator driver amplifier ICs based on InP/InGaAs HBT technology

We demonstrated first 50-Gbit/s operation of AGC and modulator driver amplifier ICs based on InP/InGaAs heterojunction-bipolar-transistor (HBT) technology aimed for 40-Gbit/s optical transceivers equipped with over 20% forward error correction (FEC).