Dispersion pre-compensation of 25.6 Tbps waveforms using an optical frequency comb synthesizer/analyzer

In this study, we propose and demonstrate a dispersion compensation system for an ultrafast 25.6 Tbps waveform using multilevel 8-ary amplitude and 32-ary phase modulation. The waveform bit period was 312.5 fs, which was controlled and compensated by a 200 GHz optical frequency comb (OFC) synthesizer with a 6.4 THz bandwidth. Dispersion spectra were measured in parallel and simultaneously (within 1 ms), based on single-shot dual-heterodyne mixing by introducing an OFC and arrayed waveguide grating to separate sidebands. An optical pulse synthesizer (OPS) can individually control the phase and amplitude spectra of the OFC. To control transmitted waveforms in a dispersed media, the OPS can be oppositely biased to feed the measured dispersion back into the source waveform when it generates an arbitrary waveform. In this study, a 25.6 Tbps dispersion-free waveform was successfully transmitted through a 10.55 km fiber.