Polarisation demultiplexing in coherent receivers with real-time digital signal processing

We report on a blind polarization demultiplexing algorithm for arbitrarily shaped complex-modulated signals. The technique evaluates sums of moduli of the received complex-valued electric field, is computationally very efficient, and thus suited for real-time applications. Prior to polarisation demultiplexing neither data demodula-tion nor timing or carrier recovery is required. Our procedure combines the numerical simplicity of the constant modulus algorithm with the versatility of the Stokes space approach. Experiments confirm our findings.