Compromised extinction and signal-to-noise ratios of weak-resonant-cavity laser diode transmitter injected by channelized and amplitude squeezed spontaneous-emission

By using a 200GHz AWG channelized ASE source in connection with a saturable semiconductor optical amplifier (SOA) based noise blocker as the injecting source at the remote node in front of the local optical network units (ONUs), we demonstrate the spectrum-sliced ASE transmitter with greatly suppressed intensity noise performance in WDM-PON network. Such channelized SOA filtering technique effectively reduces the relative intensity noise of the ASE source by at least 4.5 dB. The low-noise WRC-FPLD transmitter improves its extinction-ratio (ER) from 8.9 to 9.6 dB and signal-to-noise ratio (SNR) from 5.9 to 6.3 dB. In comparison with broad-band ASE injection-locked WRC-FPLD transmitter at same power, there is an improvement on receiving power penalty (Delta P-Receiver) by 2 dB at BER 10(-9) in back-to-back case, and the receiving power of BER 10(-9) can achieve -24 dBm even after 25km fiber transmission. With additional AWG filtering, the intraband crosstalk effect between the upstream transmitted data and the reflected ASE signal is significantly reduced by 6.3dB. The compromised effects of ER and SNR on BER performance are also elucidated via the modified SNR model for the WRC-FPLD under ASE injection induced gain-saturation condition. The Delta P-Receiver/Delta SNR of 8.89 at same ER condition is more pronounced than the Delta P-Receiver/Delta ER of 3.17 obtained under same SNR condition, indicating that the SNR plays a more important role than the ER on enhancing the BER performance. (C) 2009 Optical Society of America