Bi-directional optical add-drop multiplexer

摘要

A bi-directional optical add-drop multiplexer is disclosed. The multiplexer includes at least two couples of optical elements including a wavelength division multiplexer and an optical circulator. Each of the wavelength division multiplexer demultiplexes one of a first WDM optical signal and a second WDM optical signal transmitted in opposite directions through one optical transmission line between nodes of a bi-directional WDM optical communication network, drops an optical signal having a predetermined wavelength from the demultiplexed signals, and adds an optical signal having a predetermined wavelength to the other of the first WDM optical signal and the second WDM optical signal. The optical circulator separates routes for the signals dropped and added by a corresponding wavelength division multiplexer. The bi-directional optical add-drop multiplexer can prevent or reduce degradation of optical signal transmission quality due to crosstalk between an added optical signal and a dropped optical signal.