Polarization-Insensitive Wavelength Conversion by FWM in a Highly Nonlinear PCF of Polarization-Scrambled 10-Gb/s RZ-OOK and RZ-DPSK Signals

Wavelength conversion of polarization-scrambled 10-Gb/s on-off keyed and differential phase-shift-keyed signals for which the pulse format was 33% return-to-zero, has been achieved by partially degenerate four-wave mixing in a record 20-m-short highly nonlinear photonic crystal fiber. It was found that a minimum pump-probe detuning of ~9 nm was required to achieve polarization-insensitive wavelength conversion of <1 dB, resulting in a 10^-9-receiver sensitivity penalty of <1 dB, for both modulation formats.