A novel bidirectional add/drop amplifier (BADA)

We demonstrate a novel bidirectional add/drop amplifier (BADA) module by using only one N/spl times/N arrayed-waveguide grating (AWG). For the effective transmission of bidirectional signals, it is essential to suppress the relative intensity noise caused by Rayleigh backscattering, multiple reflection, and/or AWG crosstalk. The proposed amplifier module can suppress the relative intensity noise simply by using two optical bandpass filters. No degradation was observed in the receiver sensitivity when these amplifier modules were used for the bidirectional transmission and add/drop multiplexing of wavelength-division-multiplexing signals.