A 160-gb/s group-alternating-phase CSRZ format

We demonstrate a novel 160-Gb/s modulation format that employs phase inversion of every four consecutive bits in a group. This format enables a very simplified clock recovery by optical filtering of 40-GHz spaced tones. The recovered clock shows a low timing jitter of 270 fs. In addition, we investigate its enhanced nonlinear transmission property by comparing it with carrier-suppressed return-to-zero (CSRZ) and pairwise-alternating-phase CSRZ signals through analytical studies and numerical simulations. We experimentally verify its good performance relative to CSRZ through a data transmission over a 38-km single-mode fiber.