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
noise
coherent optical communication
probability
compensation
Clock recovery
systems
timing
fiber optics
amplifiers
modified Cramer-Rao bound
optical-fibers
Author
Ahmet Serdar Tan
Chalmers, Signals and Systems, Kommunikationssystem, informationsteori och antenner
Henk Wymeersch
Chalmers, Signals and Systems, Kommunikationssystem, informationsteori och antenner
Pontus Johannisson
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Erik Agrell
Chalmers, Signals and Systems, Kommunikationssystem, informationsteori och antenner
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 6189720Subject Categories (SSIF 2011)
Telecommunications
DOI
10.1109/jlt.2012.2196407