Polarizaton diversity for optical fiber applications

An apparatus for recovering optical signals carried by optical cable that have at least one region intermediate a signal encoding source and an optical receiver, where the at least one region is subjected to physical vibration resulting in undesired polarization changes in the light beams carried by the optical fibers, the apparatus comprising:

• light transmission source disposed on a watercraft;
• towed sensor array, designed to be towed under water behind the watercraft, contains a signal encoding source;
• optical cable connecting the light transmission source and signal encoding source where the optical cable transmits a source of light from the light transmission source to the signal encoding source;
• the signal encoding source generating, based on the light received from the light transmission source, first and second light beams each carrying a representation of the same information where the second light beam has a polarization that is substantially different from the first light beam;
• an optical receiver disposed on the watercraft;
• first and second optical fibers connected to the optical receiver and signal encoding source where the first and second optical fibers transmit the first and second light beams respectively from the signal encoding source to the optical receiver, the first and second fibers subjected to said physical vibration that is due to tow cable strum;
• the optical receiver detecting information carried by the first and second light beams by using benefits of polarization diversity to minimize degradation of signal recovery due to the adverse polarization changes caused by vibration of the first and second optic fibers.

A submersible towed sensor array that generates optical signals carried by optical fibers that have at least one region intermediate a signal encoding source and an optical receiver disposed on a watercraft, where the at least one region is subjected to physical vibration resulting in undesired polarization changes in the light beams carried by the optical fibers, the towed sensor array comprising:

• said optical fibers;
• the signal encoding source is coupled to the optical fibers and generates first and second light beams each carrying a representation of the same information where the second light beam has a polarization that is substantially different from the first light beam;
• the optical fibers including first and second fibers, the signal encoding source transmitting the first and second light beams respectively on the first and second fibers,
• the first and second fibers traversing the at least one region, being subjected to said physical vibration and being adapted to be coupled to the optical receiver so that benefits of polarization diversity can be derived from the first and second light beams by the optical receiver to minimize degradation of signal recovery due to adverse polarization changes caused by vibration of the first and second optic fibers.