Pulsewidth Tunable and Polarization-Insensitive NRZ-to-RZ Conversion by Using Fiber Nonlinearity Based Circuits

摘要

We demonstrate a polarization-insensitive non-return-to-zero (NRZ) to pulsewidth tunable return-to-zero (RZ) conversion based on a fiber based NRZ-to-RZ converter which consists a polarization diversity loop and a Raman amplifier (RA)-based pulse compressor. In our scheme, polarization insensitive operation is achieved due to the polarization diversity loop with a polarization beam splitter (PBS) inside this loop. The signals enter the PBS and propagate both of the directions inside the loop before entering the highly nonlinear fiber (HNLF). Moreover, by changing the Raman pump power of the RA-based pulse compressor in this scheme, the pulsewidth of the converted RZ signal can be flexibly tuned from 10 ps to 2 ps.%偏波ダイバシティループとラマンソリトン圧縮器を用いた偏波無依存及びパルス幅可変動作が可能なNRZ-to-RZ変換器を実現した。偏波ビームスプリッダ(PBS: Polarization Beam Splitter)を用いたループ回路によって偏波無依存動作が得られる。出力RZ信号のパルス幅はラマンソリトン圧縮器のラマン励起光パワーを調整することで2ps〜10 psの範囲で制御が可能である。