All-optical noise cleaning based on co-propagating lossless polarization attraction

We exploit a recently proposed nonlinear lossless polarizer to suppress the noise component that is (bitwise) orthogonal to an optical signal. It is shown how the proposed technique yields an optical signal-to-noise ratio (OSNR) gain close to 3dB and how this gain can be theoretically predicted, for different input OSNR values, from the degree of polarization (DOP) of the repolarized output signal.