基于光子晶体光纤中双抽运四波混频效应的非归零到归零码型转换实验研究

提出并实验证实了利用色散平坦高非线性光子晶体光纤中双抽运四波混频效应实现非归零 (NRZ)到归零(RZ)码型转换的新方案, 将一束NRZ信号光与两束同步时钟脉冲光同时注入光子晶体光纤, 通过双抽运四波混频效应产生两个闲频光, 经过光学滤波后即可完成单到双全光NRZ-RZ码型转换. 与基于常规单抽运四波混频效应的码型转换方式相比, 本设计方案由于采用了双抽运四波混频效应, 因此具有双路组播信号波长可彼此独立选取的优点. 分析了码型转换器的波长调谐性及对输入光功率波动的容忍性, 得到转换信号的最优消光比和Q 因子分别为15 dB和5.4. 研究结果表明, 本方案既具有对比特率和调制格式透明的优点, 又避免了使用单抽运四波混频效应进行码型转换时两路组播信号波长相互制约的弊端, 且实现了全光波长转换和波长组播功能. 关键词： 码型转换 四波混频 双抽运 光子晶体光纤

All-optical format conversion from non-return-to-zero to return-to-zero based on dual-pump four-wave mixing in photonic crystal fiber

A novel all-optical format conversion scheme based on dual-pump four-wave-mixing (DP-FWM) in dispersion-flattened highly nonlinear photonic crystal fiber (DF-HNL-PCF) is proposed and experimentally demonstrated. The original non-return-to-zero (NRZ) format is converted into double return-to-zero (RZ) format by injecting NRZ signal and double synchronized clock signals into the DF-HNL-PCF. The DP-FWM effect generates two sideband components, which carry the same data information as the original NRZ signal with RZ format. The wavelength tunability and dynamic range of format converter are investigated. The optimum extinct ratio and Q factor of converted signals are 15 dB and 5.4, respectively. The advantages of this scheme are that the each wavelength of double channel multicasting signals is dependent and flexible. Moreover, the system is transparent to bit rate as well as modulation format, and achieves all-optical wavelength conversion and wavelength multicasting.
Keywords： format conversion four-wave mixing dual-pump photonic crystal fiber