Electronic demultiplexing for dual-polarization (DP) intensity-modulated direct detection (IMDD) optical communication systems

A dual-polarization (DP) intensity-modulated direct detection (IMDD) receiver comprising:

• an input port configured to receive input light;
• an optical polarization splitter configured to split the input light into a pair of optical transmission paths;
• a pair of photodetectors comprising (i) a first photodetector configured to detect light at a first carrier frequency and output an electrical signal into a first electrical transmission path, and (ii) a second photodetector configured to detect light at a second carrier frequency and output an electrical signal into a second electrical transmission path, wherein the first carrier frequency and the second carrier frequency are separated by a frequency difference, wherein the frequency difference is configured to cause the light detected at the first photodetector and the light detected at the second photodetector to be heterodyne-multiplexed;
• and
• an electrical 2×2 multi-input-multi-output (MIMO) polarization demultiplexer configured to receive signals from the first electrical transmission path and the second electrical transmission path and, based on the light detected at the first photodetector and the light detected at the second photodetector being heterodyne-multiplexed, perform electrical 2×2 MIMO polarization demultiplexing to output a first demultiplexed signal and a second demultiplexed signal,
• wherein the DP-IMDD receiver is configured to output the first demultiplexed signal and the second demultiplexed signal using intensity-modulated direct detection.