Linear and nonlinear performance of 42.7-Gb/s single-polarization RZ-DQPSK format

We experimentally examine the performance of a single-polarization 42.7-Gb/s return-to-zero differential quadrature phase-shift keying optical signal. We evaluate the penalties arising from chromatic dispersion, polarization-mode dispersion, narrowband optical filtering, and nonlinear transmission over standard single-mode fiber.

I. Introduction

The differential quadrature phase-shift keying (DQPSK) optical modulation format has been studied intensely over the last few years. The per-channel bit rate of experiments using single-polarization channels has ranged from 10 [1], [2] through 20 [3]–[4] [5] to 80 Gb/s [6]. Fig. 1. (a) RZ-DQPSK transmitter. (b) RZ-DQPSK receiver. (c) Signal constellation and eye diagrams of intensity and differential phase.