Ryosuke Kuribayashi

A 10 Gbps x 12 channel pluggable optical transceiver for high-speed interconnections

We developed a 10 Gbps x 12 channel pluggable optical transceiver. It consists of three photoelectric devices, an FR4 substrate with a microcontroller, a 12 x 2 multimode fiber with three optical connectors for the three photoelectric devices, an electrical connector, and a heat sink. This transceiver can be vertically plugged to the motherboard by using electrical connector. A vertical plug enables the photoelectric conversion devices in the optical transceiver to be located close to the logic LSI on the motherboard at high density to prevent the waveform degrading. Moreover, it is possible to do prompt repairs if the transceiver breaks down because the module is pluggable. We demonstrated error-free operation after 50 m transmission over a GI/50 multimode fiber (MMF). These performance characteristics indicated that this optical transceiver is feasible for implementation in high- throughput interconnections.

A 400 Gbps backplane switch with 10 Gbps/port optical I/O interfaces

A 400 Gbps backplane switch was developed with low-cost, small-size, 8-channels 10 Gbps/port optical I/O and a SiGe Bi-CMOS switch LSI on a 60x60-mm2 BGA package. It indicates the applicability of backplane switch for high throughput backplane interconnections.

40-GHz tunable optical pulse generation from a highly stable external-cavity mode-locked semiconductor laser module

In conclusion, we have demonstrated that a stable EC-MLLD module can generate wavelength tunable optical clock pulses up to 40-GHz by higher-harmonic hybrid mode-locking. Our EC-MLLD which has flexible tunabilities in wavelength, pulse repetition frequency, and pulse width will be very beneficial for the evaluation and the optimization of 40-Gbit/s based optical communication systems.

Development of Alicyclic Polymers for Multimode Waveguide Array and its Characteristics for Use in Optical Interconnection

We have carried out elemental research and development regarding optical transmission technology to establish the petaFLOPS - (1015 floating point number operations per second) class supercomputer. We describe our development of an alicyclic polymer, waveguide arrays formed with the polymer, and their characteristics for multimode optical data transmission. We have also developed high-density optoelectronic modules with a 4.5times4.5times0.5-mm low-temperature co-fired ceramic (LTCC) substrate that transmits 12 signals, and demonstrated a 10-Gbps/ch error-free transmission with the polymeric-waveguide array. We also showed a 20-Gbps/ch optical eye as a transmitter with a 1.1-mum range InGaAs vertical-cavity surface-emitting laser (VCSEL).

Optical signal processing using mode-locked semiconductor laser diode

We investigated ultrafast optical signal processing schemes utilizing mode-locked semiconductor laser diodes (MLLDs) for optical time-division multiplexing (OTDM) transmission at over 100 Gbit/s and developed a polarization-insensitive all-optical clock recovery scheme for an optical-electrical hybrid phase-locked loop (PLL) operating at 160 Gbit/s. In this scheme, the MLLD functions as a voltage-controlled oscillator to which the error signal is fed back by forming a closed loop with a semiconductor optical amplifier (SOA) used as a phase comparator and with a low-frequency component used as a filter. Cross-gain modulation in the SOA enables high-frequency PLL operation at 160 Gbit/s. A bulk active layer in the SOA with small polarization dependency is the origin of the polarization insensitive clock extraction. Testing of all-optical clock extraction on an OTDM transmission test bed of 254-km field-installed fibers (Dojima-Keihanna, 63.5 km, and four spans) at 160 Gbit/s showed that the measured root-mean-square timing jitter of the recovered clock signal was as low as 240 fs. This clock extraction scheme is thus practical for use in OTDM systems operating at over 100 Gbit/s.