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Patents
Patents Assigned to University of Southern California (LA)
Patents Assigned to University of Southern California (LA)
MONITORING AND IN-LINE COMPENSATION OF POLARIZATION DEPENDENT LOSS FOR LIGHTWAVE SYSTEMS
Publication number:
20080038000
Abstract:
A multi-wavelength optical signal copropagates through a fiber-optic communication link with a continuous-wave ancillary wavelength having an unknown state of polarization (SOP), which is scrambled periodically in time. The instantaneous value of polarization dependent loss (PDL) in the ancillary wavelength is monitored in real time, and is used as an error signal to adjust at least one polarization controller. Polarization scrambling is performed by periodically changing the SOP with time, such that the polarization-scrambled optical signal covers approximately an entire Poincaré sphere surface, preferably uniformly, during each time period. At an optical node between fibers, an adjustable PDL compensator contains two ordered pairs each consisting of one polarization controller and one optical element introducing fixed PDL.
Type:
Application
Filed:
April 16, 2007
Publication date:
February 14, 2008
Applicant:
University of Southern California (LA)
Inventors:
Qian Yu, Lianshan Yan, Alan Willner
Monitoring and in-line compensation of polarization dependent loss for lightwave systems
Patent number:
7206517
Abstract:
A multi-wavelength optical signal copropagates through a fiber-optic communication link with a continuous-wave ancillary wavelength having an unknown state of polarization (SOP), which is scrambled periodically in time. The instantaneous value of polarization dependent loss (PDL) in the ancillary wavelength is monitored in real time, and is used as an error signal to adjust at least one polarization controller. Polarization scrambling is performed by periodically changing the SOP with time, such that the polarization-scrambled optical signal covers approximately an entire Poincaré sphere surface, preferably uniformly, during each time period. At an optical node between fibers, an adjustable PDL compensator contains two ordered pairs each consisting of one polarization controller and one optical element introducing fixed PDL.
Type:
Grant
Filed:
March 15, 2002
Date of Patent:
April 17, 2007
Assignee:
University of Southern California (LA)
Inventors:
Qian Yu, Lianshan Yan, Alan E. Willner