Polarization Independent All-optical Clock Recovery Scheme based on Birefringent Resonator

We introduce a polarization insensitive scheme for all-optical clock recovery and demonstrate how it works with data signals highly distorted by chromatic dispersion and self-phase modulation. The scheme which is known for its multi-wavelength and multi-data-rate capabilities is based on a birefringent fiber resonator and a polarizer. In this article we show how it can handle data signals which have undergone distortion due to transmission over dispersive and nonlinear fiber-optic propagation paths and which come in with arbitrary polarization orientation. Bit-pattern dependent amplitude fluctuations of the recovered clock signal are equalized by means of a semiconductor optical amplifier operated in saturation. The experimental results which, as a proof-of-concept, are obtained from single-wavelength channel 10 Gbit/s return-to-zero data agree well with numerical simulations.