Dual-Stage Cascaded Frequency Offset Estimation for Digital Coherent Receivers

• Published in: IEEE photonics technology letters Vol. 22; no. 6; pp. 401 - 403
• Main Authors: Zhang, S., Xu, L., Yu, J., Huang, M.-F., Kam, P.Y., Yu, C., Wang, T.
• Format: Journal Article
• Language: English
• Published: New York IEEE 15-03-2010; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Coherence; Coherent optical communication; Conferences; Digital; Feedforward systems; Fiber optics; Frequency estimation; frequency offset; Offsets; Optical fiber communication; Optical fibers; Optical receivers; Optical transmitters; Phase estimation; Phase shift keying; Quadrature phase shift keying; Receivers; Signal processing algorithms; Simulation; Timing; timing recovery
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2010.2040171

Frequency offset estimation is a key function in carrier phase recovery to enable digital coherent reception. We propose a novel, feed-forward, dual-stage frequency offset estimator, and demonstrate its performance through both simulation and experiment. Our simulation results show that the estimation range can be as large as ± 9 GHz for a 10.7-GBaud polarization-multiplexed (PolMux) quadrature phase-shift keying (QPSK) system. In addition, the widest range of ±0.5 times the system symbol rate is achieved for the first time in an experimental 42.8-Gb/s coherent PolMux QPSK receiver.