Digital coherent optical receiver, adaptive equalizer, and digital coherent optical communication method

摘要

A digital coherent optical receiver includes an equalizing filter, a histogram generation device and a determination device. The equalizing filter separates electric signals obtained by converting an optical signal into a horizontal signal component and a vertical signal component. The histogram generation device generates a histogram of the horizontal signal component and the vertical signal component as outputs of the equalizing filter. The determination device determines the presence/absence of local convergence by comparing the number of pieces of data or the amplitude value of the histogram of the horizontal signal component and the histogram of the vertical signal component with the reference value.