Experimental Demonstration of Optical DQPSK Receiver Based on Frequency Discriminator Demodulator

This paper presents experimental data demonstrating a novel differential quadrature phase-shift keying receiver based on optical frequency discriminator demodulator with direct detection. The experimental results confirm theory, showing a factor of 2times enhanced tolerance to chromatic dispersion compared with a conventional delay-interferometer-based demodulator with balanced detection. The frequency discriminator direct detection receiver also shows a significant improvement in tolerance to Gordon-Mollenauer nonlinear phase noise.