POLARISATION MODE DISPERSION COMPENSATOR USING A MEAN SQUARE ERROR TECHNIQUE

摘要

A method for the adaptive adjustment of a PMD compensator in optical fiber communication systems comprises the steps of taking the signal at the compensator output and extracting the components y₁(t) and y₂(t) on the two orthogonal polarizations, computing the signal y(t)=[y₁(t)]²+[y₂(t)]², sampling the signal y(t) at instants t_k=kT with T=symbol interval to obtain samples y(t_k), computing the mean square error e(k)=y(t_k)-u(k) with u(k) equal to the symbol transmitted, and adjusting the parameters of the compensator to seek to minimize e(k). A PMD compensator in accordance with the method comprises an adjustment system which comprises in turn a photodetecor ( 17 ) which takes the components y₁(t) and y₂(t) on the two orthogonal polarizations from the signal at the compensator output, a sampler ( 19 ) which samples at instants t_k=kT with T=symbol interval, the signal y(t)=[y₁(t)]²+[y₂(t)]² at the output of the photodetector ( 17 ) to obtain samples y(t_k), a circuit ( 18, 20 ) for computation of the mean square error e(k)=y(t_k)-u(k) with u(k) equal to the symbol transmitted, and a regulator ( 15, 16 ) which regulates the parameters of the compensator to seek to minimize e(k).