Optical feed-forward equalizer for MIMO signal processing

摘要

A feed-forward equalizer can be used in the host optical receiver to perform at least some of the desired signal processing in the optical domain, e.g., prior to coherently detecting and digitizing the received optical signal(s). In some embodiments, the signal processing implemented in the feed-forward equalizer can at least partially compensate the adverse effects of chromatic dispersion, polarization-mode dispersion, and/or spatial-mode mixing/crosstalk imparted on the received optical signal(s) in the optical transport link. This reduces the signal-processing load of and the signal-processing requirements to the receiver's electrical DSP.

主权项

1. An apparatus comprising an optical feed-forward equalizer configured to be coupled between an input fiber and a plurality of output fibers, wherein said feed-forward equalizer comprises:
an optical splitter configured to optically split light received from the input fiber into a plurality of sub-beams; and a plurality of spatial light modulators (SLMs), wherein: the optical splitter is further configured to apply a respective subset of said plurality of sub-beams to each of the plurality of SLMs such that different sub-beams of the respective subset impinge on different respective portions of a respective SLM; each of the plurality of SLMs is configured to (i) receive said respective subset of said plurality of sub-beams from the optical splitter with relative time delays with respect to one another and (ii) spatially modulate each of the received sub-beams to generate a respective modulated beam; and the feed-forward equalizer is configured to couple the modulated beams generated by each of the plurality of SLMs into a respective output fiber of the plurality of output fibers.