A novel frequency detector for DP-QPSK receivers using sine-cosine sampling method

To cater to the demand for ever increasing Internet traffic, on-off keying over multi-mode fiber is expected to be replaced with coherent signaling over single mode fiber in short-reach optical interconnects. One of the key challenges faced at the receiver-end is the recovery of the frequency and phase of the transmitter laser. We propose a novel frequency detector that uses sine-cosine sampling method which can be used in a carrier phase recovery and compensation loop. System level simulations of the proposed detector show promising results.