Modified Cramer-Rao Bound for Clock Recovery in the Presence of Self-Phase Modulation
Magazine 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.

design

Clock recovery

compensation

optical-fibers

fiber optics

modified Cramer-Rao bound

noise

coherent optical communication

timing

systems

amplifiers

probability

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

3/29/2018