Patent ID: 8655190

Claim:
An apparatus, comprising: a substrate; an optical splitter provided on the substrate, the optical splitter having an input and a plurality of outputs, the optical splitter receiving a wavelength division multiplexed (WDM) optical signal including plurality of optical signals, each having a corresponding one of a plurality of wavelengths, each of the plurality of outputs of the optical splitter supplying a corresponding one of a plurality of first portions of the WDM optical signal; a plurality of local oscillator lasers provided on the substrate; a plurality of optical hybrid circuits provided on the substrate, each of the plurality of optical hybrid circuits having a first input coupled to a corresponding one of the plurality of outputs of the optical splitter and a second input configured to receive a first portion of light supplied by a corresponding one of the plurality of local oscillator lasers, each of the plurality of optical hybrid circuits having an output that supplies a corresponding one of a plurality of second portions of the WDM optical signal and a second portion of the light supplied by a corresponding one of the plurality of local oscillator lasers, each of the plurality of second portions of the WDM optical signal including light at each of the plurality of wavelengths; a plurality of photodiodes provided on the substrate, each of which receiving a respective one of the plurality of second portions of the WDM optical signal and the second portion of the light supplied by a corresponding one of the plurality of local oscillator circuits, each of the plurality of photodiodes supplying a corresponding one of a plurality of electrical signals; a plurality of low-pass filters, each of which supplying a corresponding one of a plurality of filtered outputs in response to a respective one of the plurality of electrical signals; an analog-to-digital converter configured to sample one of the plurality of filtered outputs at a first sampling rate to generate a plurality of first data samples; an interpolation circuit configured to receive the plurality of first data samples and supply a plurality of second data samples at a second sampling rate less the first sampling rate; and a digital signal processor circuit configured to receive the plurality of second data samples.