WDM receiver with integrated optical preamplifier, aspheric lens and grating filter

A photonic integrated circuit implementing a receiver with an optical preamplifier and a wavelength filter for dense WDM systems has been fabricated. The integrated filter is based on planar optics and formed by a waveguide lens and Bragg grating combination. This arrangement provides a narrow filtering response of 0.4 nm and a high sidemode rejection ratio of 20 dB. A monolithically integrated preamplifier and photodetector are also incorporated to allow for high-sensitivity and high-speed operation.