Broad-band tunable four wave mixing based wavelength converter with filterless pump suppression

We propose and compare three schemes for realizing pumps suppression in a Broad- and flat-band tunable four wave mixing (FWM) wavelength converter (WC) without using a high-speed tunable filter. The signal and pumps are coupled into a high-nonlinear symmetrical Sagnac loop, after the FWM process, the idler and pump exit from different ports of the Sagnac loop. The idler to pump suppression ratio can be further improved by improving the symmetry of the loop, such as by improving the performance of the 3 dB coupler.