title: Simultaneous nominal and effective differential group delay in-service monitoring method for optical communications systems.
abstract: In this paper, we propose an in-service method to simultaneously monitor both nominal and effective values of differential group delay (DGD) in wavelength-division multiplexing (WDM) optical communication systems, in a per channel basis. The method is based on coherent heterodyne detection of the optical signal. We have demonstrated that the technique is capable to recover nominal DGD values from 0 ps to 90 ps while, at same time, to provide the effective DGD parameter, related to the impairment of optical channels. The relationship between the Q factor and effective DGD was also demonstrated, both numerically and experimentally, for distinct nominal values of DGD inserted on the system, by varying the state of polarization (SOP) of the optical signal at the input of the DGD element.
authors.affiliation: CPqD Foundation - Research and Development Center in Telecommunication, Rod. Campinas-Mogi Mirim, km 118.5, Campinas, SP, 13086-902, Brazil. gsimoes@cpqd.com.br
authors.forename: Glauco C C P
authors.initials: GC
authors.lastname: Simões
authors.forename: Claudio
authors.initials: C
authors.lastname: Floridia
authors.forename: Carolina
authors.initials: C
authors.lastname: Franciscangelis
authors.forename: Márcio C
authors.initials: MC
authors.lastname: Argentato
authors.forename: Murilo A
authors.initials: MA
authors.lastname: Romero
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D055096:Optical Devices; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*