Widely tunable wavelength conversion with extinction ratio enhancement using PCF-based NOLM

A widely tunable wavelength conversion scheme has been demonstrated using a 64-m-long dispersion-flattened high-nonlinearity photonic crystal fiber in a nonlinear optical loop mirror. Wavelength conversion range of over 60 nm with a 10-Gb/s return-to-zero signal was obtained with the output extinction ratio (ER) maintained above 13 dB. The proposed scheme can also improve the output ER and remove the bit-error-rate floor if a degraded signal is used.