Satoshi Shirai

Dual-rate optical transceiver incorporating fully optimized burst-mode AGC/ATC functions for 10G-EPON systems

10G-EPON dual-rate transceiver with receiver sensitivity of −30.8dBm for 10.3125Gb/s and −35.5dBm for 1.25Gb/s due to fully optimized burst-mode AGC/ATC functions was developed. A high launch power and low dispersion penalty transmission were also achieved.

Super-splits 10G-EPON system: 256 ONU passive splits with 240 ns dual-rate burst-mode 3R synctime and bi-directionally extended 35.9 dB loss budgets

This first super-splits 10G-EPON demonstration achieved the largest loss budget of 35.9 dB and a fast dual-rate synctime of 240 ns supporting 256 ONU splits with 8.0 Gb/s upstream throughput, highlighting novel self-switching AGC based XFP, 82.5 GS/s CDR and ONU SFP+.

Uncooled directly modulated 1.3-μm AlGaInAs-MQW DFB laser diodes

We have proved that short cavity length and large coupling coefficient structure can increase the relaxation oscillation frequency of directly modulated 1.3mm DFB-LDs for 10Gb/s operation. The grating with large coupling coefficient can be made of high refractive index InGaAsP material (=narrow band gap energy material), which has to be fabricated in the n-type InP cladding layer to prevent large hole and electron accumulation in the grating layer. By using this grating, 1.3mm AlGaInAs quarter lambda phase shifted DFB-LDs successfully revealed excellent eye diagrams with over 10% margin for OC-192 mask at the temperature range of 25-95 deg.C. Furthermore, we newly propose multi-phase shifted gating to 10Gb/s quarter lambda phase-shifted DFB-LDs to suppress the deterioration of eye diagrams due to non-uniform longitudinal distribution of light intensity and carrier density.

Recent progress of high-speed burst-mode transceiver technologies for TDM-PON systems

In this paper, we report on the performances both of ONU and OLT transceivers for 10G-EPON systems including dynamic power saving technology and 10G/1G dual-rate receiving technology. The dynamic power saving technology for ONU can realize fast response less than 736 ns and high power consumption degradation more than 38 % in the heavy uplink traffic conditions. On the other hand, OLT receiver can achieve high receiver sensitivity for each 10G and 1G less than -30.6 dBm and -34.6 dBm, respectively, with fast receiver settling times of 800 ns for 10G and 400 ns for 1G.

N2a-compliant SFP+ OLT transceiver for high power budget XG-PON systems

We developed an SFP+ size N2a-compliant optical transceiver for XG-PON systems with a high minimum receiver sensitivity of −32.5 dBm and a rapid receiver settling time of 20 ns by using a burst-mode preamplifier with a peak-detecting AGC circuit incorporating a self-locking function. A high optical output power of +5.7 dBm and a low dispersion transmission penalty of 0.4 dB were also achieved.