Photonic-assisted seamless channelization based on integrated three-stage cascaded DIs

A novel photonic-assisted approach to realize seamless channelization based on silicon-on-insulator (SOI) integrated cascaded delay interferometers (DIs) is proposed and demonstrated. In this approach, cascaded DIs provides uniform spaced filters for different channels and a flat optical frequency comb (OFC) is used as local oscillator (LO) for frequency down-conversion. Since the frequency spacing of OFC is set to be twice of channel interval and IQ demodulation scheme is employed, cross talk from different channels can be eliminated. In addition, we designed the overlapped position of the two adjacent channels to be just 3dB lower than the filter peak for covering the whole spectrum seamlessly. This new concept has been testified with an experimental 8-channel receiver of 12.8-GHz bandwidth.