Flexible, compact WDM receivers using cascaded optical and electrical down-conversion.

We propose a super-channel flexible wavelength division multiplexing (WDM) receiver architecture. The receiver, which requires no optical filtering, only a pair (I and Q phases) of coherent optical detectors, and an electrical receiver system, can simultaneously recover multiple wavelength-multiplexed channels using cascaded optical and electrical down-conversion. The receiver data capacity increases in proportion to the number of electrical sub-carrier channels. The proposed receiver concept has been described using a six-channel WDM receiver, and a two-channel ( ± 25 GHz) receiver IC, which is a key block of the WDM receiver, has been successfully demonstrated with two and three 2.5 Gb/s binary-phase-shift-key (BPSK) modulated channels.