An all-optical signal processor enabling terabit-per-second real-time equalization

Large-scale artificial intelligence training demands ultralow-latency, energy-efficient interconnects for massive graphics processing unit clusters. In intensity-modulation/direct-detection links, digital signal processing (DSP) equalization is limited by nonideal equalization caused by phase loss as well as tight power and latency budgets. We present an integrated, programmable optical signal processor (OSP) that functions as a nonlinear universal equalizer and performs all-optical, DSP-free, real-time equalization. A deep reservoir with all-optical readout enables a Vernier scheme with ~1-picosecond (ps) sampling resolution and a tunable memory window. The OSP simultaneously equalizes eight wavelength-division-multiplexing (WDM) channels, delivering 1.6-terabits/second aggregate throughput with <60-picoseconds latency and tens of femtojoules/bit energy consumption. Operating before detection, it provides superior chromatic dispersion compensation, mitigates transceiver bandwidth limits and fiber nonlinearity, and expands the usable WDM window by a factor of 6.8.