Optical multilevel signal pre-equalization circuit, optical multilevel signal pre-equalization transmitter, and polarization-multiplexed pre-equalization transmitter

摘要

In order to reduce the circuit size for a chromatic dispersion pre-equalization operation, an optical multilevel signal pre-equalization circuit is provided with: (1) a plurality of look-up tables in which a string of middle codes 124 utilizing a symmetry of a signal constellation of a multilevel code or a string of middle codes 124 represented by polar coordinates is stored in association with a waveform response component; and (2) one or more operation circuits to which the waveform response component corresponding to a multilevel signal 107 to be transmitted is inputted from the plurality of look-up tables 124, and which outputs a pre-equalized output waveform corresponding to the multilevel signal 104 by operating the waveform response components outputted from different look-up tables 124.