System performance of a 4-channel PHASAR WDM receiver operating at 1.2 Gbit/s

Phased arrays are important key components in wavelength-division multiplexing (WDM) systems. We have realized a 4-channel WDM receiver combining a phased array with photodetectors on InP with a Si bipolar transimpedance amplifier. The channels are spaced at 2.0 nm with a 1.0-nm flat passband. On chip loss was 6-7 dB and detector efficiency was better than 90%. The optical cross talk remains below -20 dB. The electrical bandwidth per channel was 1 GHz. The electrical cross talk at 1 GHz after detection is below -25 dB. We have tested this receiver in a full 4-channel system.