Polarization Insensitive Wavelength Conversion by FWM of Multiformat DWDM Signals Using Birefringent PCF

Abstract

We demonstrate all-optical wavelength conversion of four channels of polarization scrambled 10 Gb/s dense wavelength division multiplexed signals consisting of both nonreturn-to-zero-ON-OFF-keyed and differential-phase-shift keyed signals using 20 m of nonlinear birefringent photonic crystal fiber (PCF). Power penalties <;0.5 dB were achieved for a conversion bandwidth of 22 nm with four-wave mixing efficiencies between -20 and -24 dB. A rack-mount wavelength converter prototype is presented that consists of a highly tunable sample grating distributed Bragg reflector pump laser, a high-power erbium-doped fiber amplifier, a tunable bandpass filter, and a polarization controller that are all controlled using a microcontroller. Automatic polarization control of the high-power pump is demonstrated for the first time using the polarization dependence of stimulated Brillouin scattering in the PCF as a feedback mechanism.