Dispersion-tolerant 200-Gb/s OTDM-PAM4 system using a simple phase-alternating pulse generator

We propose to implement a simple 2-channel optical-time-division multiplexed (OTDM) system based on a phase-alternating pulse generator for a short-reach optical interconnects. The inserted pulse generator consisting of a phase modulator and an optical periodic filter can generate the optical pulse of which the repetition rate is double the frequency of the input electrical clock. The phase-alternating property of the pulse makes the OTDM signal robust to the chromatic dispersion. In the experiment, we optimize the optical pulse, use it for generating the 200-Gb/s OTDM signal operating in the 4-level pulse-amplitude modulated format, and transmit the signal over the 1.9-km standard single-mode fiber.