Abstract
A wavelength-division-multiplexing add/drop multiplexer (WDM-ADM) employing a novel polarisation independent acousto-optic tunable filter (PI-AOTF) and two optical circulators is proposed. The PI-AOTF consists of only one PBS and one acousto-optic TE-TM mode convertor. The polarisation dependent power fluctuation of the proposed PI-AOTF is less than 1 dB. A 3.2 nm spaced four-channel IM-DD transmission experiment at 622 Mbit/s is demonstrated. The power penalty due to the Doppler shift is 1 dB at a BER of 10−9.