COHERENT LIGHT RECEIVER, COHERENT LIGHT RECEPTION METHOD, AND INTER-CHANNEL SKEW DETECTION DEVICE AND DETECTION METHOD FOR USE IN COHERENT LIGHT RECEIVER

摘要

PROBLEM TO BE SOLVED: To solve such a problem that in a coherent light receiver, when a skew occurs between channels, sufficient demodulation becomes impossible and reception performance deteriorates.SOLUTION: A coherent light receiver according to the present invention comprises: a localized light source; a 90° hybrid circuit; a photoelectric converter; an analog-digital converter; and a digital signal processing part. The 90° hybrid circuit outputs a plurality of light signals separated into a plurality of signal components by causing a multiplexed signal light to interfere with a localized light from the localized light source. The photoelectric converter detects the light signal and outputs a detection electrical signal. The analog-digital converter quantizes the detection electrical signal and outputs the quantized signal. The digital signal processing part includes: an FFT operation part for performing high-speed Fourier transformation processing on the quantized signal; a skew compensation part for compensating for a differential delay in propagation between the plurality of signal components calculated from a result of the high-speed Fourier transformation processing; and a demodulation part for demodulating the quantized signal.