The U.S. Patent and Trademark Office has awarded patent No. 8,543,000, “System and Method for Reducing Polarization Dependent Loss Cross-Talk Effects,” to Fujitsu Ltd. in Kawasaki-shi, Japan.
According to background information provided by the inventors, the patent “relates generally to optical communication networks and, more particularly, to a system for compensating for the effects of polarization dependent loss in a system.”
“Telecommunications systems, cable television systems and data communication networks use optical networks to rapidly convey large amounts of information between remote points. In an optical network, information is conveyed in the form of optical signals through optical fibers. Optical networks may also include various network elements such as amplifiers, dispersion compensators, multiplexer/demultiplexer filters, wavelength selective switches, couplers, etc. configured to perform various operations within the network.”
“However, each of these network elements may also introduce polarization dependent effects on the signals traveling through the network. These effects may cause the various components of the polarization states of the signals to experience varying degrees of loss or gain, thus causing unequal power levels of the various polarization components of the signals. This inequality of power may cause information or data carried by the signals to become distorted or lost.”
“In accordance with the present disclosure, disadvantages and problems associated with polarization dependent loss may be reduced. In accordance with the present disclosure a system for reducing polarization dependent loss (PDL) of an optical signal comprises a delay module coupled to one or more PDL inducing network elements of an optical network. The delay module is configured to time interleave a first polarization component with respect to a second polarization component of the optical signal. The time interleaving reduces interference caused by cross-talk components associated with the first and second polarization components and induced by the PDL of the PDL inducing elements.”
“In accordance with another embodiment of the present disclosure a method for reducing polarization dependent loss (PDL) of an optical signal comprises delaying, by a delay module, a first polarization component with respect to a second polarization component to time interleave the first polarization component with respect to the second polarization component. The time interleaving reduces interference caused by cross-talk components associated with the first and second polarization components and induced by the PDL of the PDL inducing elements.”