Patent ID: 8532502

Claim:
A filter coefficient adjustment apparatus used in a polarization demultiplexer, said polarization demultiplexer demultiplexing input signals by using filters to obtain demultiplexed output signals, said filter coefficient adjustment apparatus being used for adjusting the coefficients of the filters, wherein said filter coefficient adjustment apparatus comprises: a computer, comprising a non-transitory computer readable storage medium on which a computer program is recorded, which when executed, the computer program enables the computer to implement: an logarithm partial derivative calculation unit configured to calculate the logarithm partial derivative value of a target probability density function of the demultiplexed output signals when its self-variable value is the present demultiplexed output signal value; a gradient calculation unit configured to calculate the gradient of a target optimizing function for optimizing the distribution of the multiplexing output signals based on the logarithm partial derivative value calculated by the logarithm partial derivative calculation unit; and a filter coefficient updating unit configured to update the coefficients of the filters based on the gradient calculated by the gradient calculation unit.