Simple bidirectional add/drop amplifier module based on a single multiplexer

Abstract

This invention is to construct a bidirectional WDM add/drop amplifier module for transmitting WDMS in bidirection and for adding/dropping a signal in bidirection at each node in a WDM network system using a single N.times.N multiplexer. The bidirectional WDM add/drop amplifier module 100 comprises an 8.times.8 arrayed-waveguide grating 110. The 8.times.8 arrayed-waveguide grating 110 has, at each side, a WDMS input end L4 or R4, a WDMS output end L8 or R8, three separated signal input ends L1, L2 and L3, or R5, R6 and R7, and three separated signal output ends L5, L6 and L7, or R1, R2 and R3. One L2 or R6 of the separated signal input ends is designated as an added signal input end, one L6 or R2 of the separated signal output ends is designated as a dropped signal output end, and the separated signal output ends L5 and L7, or R1 and R3 except for the dropped signal output end connected to the signal input ends L1 and L3, or R5 and R7 at the same side. The WDM add/drop amplifier module 100 comprises a circulator 140L, 140R provided at both ends of 8.times.8 arrayed-waveguide grating 110 to distinguish paths of different WDMSs and to transmit through each path respectively, an unidirectional optical band pass filter 130L or 130R provided between the WDMS output end L8 or R8 of the 8.times.8 arrayed-waveguide grating 110 and the circulator 140L, 140R to eliminate a relative intensity noise, and a bidirectional signal amplifier 120L or 120R.