All-optical low-pass filter based on cross-gain modulation in fiber optical parametric amplifier

An all-optical low-pass filter utilizing cross-gain modulation (XGM) in fiber optical parametric amplifier (OPA) has been proposed and experimentally demonstrated. In this proposed low-pass filter, the pump, signal and a continuous-wave probe were launched in the highly-nonlinear fiber (HNLF) to introduce OPA and thereby XGM effects. Pump, signals and idlers were then being separated and then filtered. With suitable time delay being introduced into different optical paths, the low-pass filter was implemented, which was verified with the experimental results of pseudo-random signal. The timing waveforms of the filtered signal were shown, followed by the transfer function of the low-pass filter's frequency response. They all showed a good agreement with the numerical results. © 2008 SPIE.link_to_subscribed_fulltex