Novel coherent self-heterodyne receiver based on phase modulation detection

Abstract

We propose a novel coherent self-heterodyne receiver structure based on phase modulation detection that potentially simplifies the frontend of a coherent optical receiver. The scheme has been demonstrated via simulations and experimentally for a 10 Gb/s DQPSK transmission system.

Phase noise monitoring for NRZ-DPSK signals using phase modulation detection

“…Then, the two arms (distorted DPSK signal arm and phase modulated-LO arm) are combined via a coupler whose output is detected by an RF spectrum analyzer. Two polarization controllers (PC4 & PC5, one on each arm of the interferometer) are employed to manually optimize the beat signal at the output, and minimize the polarization mode dispersion effect of the modulator [9]. Finally, the RF power at 10-GHz is measured to estimate the phase noise of the DPSK signal.…”

Subcarrier multiplexing based self-heterodyne coherent detection for PM-16QAM format

“…One way to resolve these problems is to use self-heterodyne (SH) coherent detection. Previously, optical SH coherent system, where a continuous wave (CW) pilot-tone (PT) light was wavelength multiplexed with differential quadrature phase shift keying (DQPSK) signals before transmission and was finally chosen as the LO light at the receiver side, was proposed to simplify the optical coherent detection [19], and improve the tolerance of laser phase noise [20]. Secondly, in order to simultaneously detect all subcarrier channels and avoid image frequency interference (IFI) arising from the energy in the mirror spectrum of the LO, two LOs are indispensable for classical intradyne detection of both subcarriers [14].…”