A WDM receiver photonic integrated circuit with net on-chip gain

We demonstrate a photonic circuit with an optical preamplifier, a WDM filter and a fast photodetector integrated on the same chip. The passive integrated filter is formed by an aspheric waveguide lens and a planar Bragg grating. This arrangements yields narrow filter response (8 Å width at -3 dB is demonstrated) and high rejection ratio of 24 dB. The optical preamplifier consisting of strained multi-quantum well layers provides sufficient amplification to overcome the passive losses. Response curves demonstrate net on-chip gain with low ripple