Modified Cramer-Rao Bound for Clock Recovery in the Presence of Self-Phase Modulation
Journal article, 2012

We investigate the effect of nonlinear self-phase modulation (SPM) on clock recovery in long-haul coherent optical communication systems with low to moderate baud rates. We consider dual-polarization, multilevel quadrature amplitude modulation, and evaluate conventional timing estimators as well as a modified Cramer-Rao bound. As the latter is hard to compute in the presence of nonlinear channel impairments, we derive an approximate closed-form expression. Contrary to linear channel impairments, the nonlinear impairments can degrade the performance for higher input powers. In addition, the bounds exhibit oscillatory behavior due to the oscillations in the signal spectrum in the presence of SPM.

coherent optical communication

compensation

Clock recovery

optical-fibers

probability

amplifiers

noise

modified Cramer-Rao bound

timing

systems

design

fiber optics

Author

Ahmet Serdar Tan

Chalmers, Signals and Systems, Communication and Antenna Systems, Communication Systems

Henk Wymeersch

Chalmers, Signals and Systems, Communication and Antenna Systems, Communication Systems

Pontus Johannisson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Erik Agrell

Chalmers, Signals and Systems, Communication and Antenna Systems, Communication Systems

Magnus Karlsson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Peter Andrekson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Journal of Lightwave Technology

0733-8724 (ISSN)

Vol. 30 16 2556-2562 6189720

Subject Categories

Telecommunications

DOI

10.1109/jlt.2012.2196407

More information

Latest update

2/18/2021