Optical DQPSK Receiver With Enhanced Dispersion Tolerance

We propose and analyze a novel differential quadrature phase-shift-keying (DQPSK) receiver architecture based on optical frequency discriminator filtering and direct detection. Our simulations show that such a receiver provides significantly enhanced tolerance to chromatic dispersion compared with the conventional delay-interferometer-based receiver. Preliminary measurement results demonstrate the novel DQPSK demodulator concept at 20 Gb/s.