Polarization diversity for optical fiber applications
AssigneeNorthrop Grumman Guidance and Electronics Company, Inc.
InventorsDavid Hall, Paul Greene
Life of this patent
Estimating the term…
Abstract
At least two light beams with polarization diversity are generated that each carry a representation of the same information. Separate optic fibers carry each of the at least two beams through a region subject to vibration to a remote location where the information is recovered by an optical receiver based on the separate light beams. Using separate fibers to carry polarization diverse information minimizes polarization noise at the optical receiver due to vibration of the fibers.
Claims23
A sensor apparatus for detecting parameters and encoding the detected parameter onto a light beam, the apparatus comprising:
- sensors adapted for detecting the parameters and encoding the detected parameters onto a first light beam;
- a first optic fiber adapted for carrying the first light beam;
- optical beam splitter coupled to the first optic fiber, said optical beam splitter adapted to receive as an input the first light beam and generate second and third optical beam outputs derived from the first light beam where the second beam has a polarization that is substantially different from the polarization of the third beam;
- second and third optic fibers that receive the second and third beam outputs, respectively, and transmit the second and third beam outputs to an optical receiver that is geographically remote from the optical beam splitter.
A sensor apparatus for detecting parameters and encoding the detected parameter onto a light beam, the apparatus comprising:
- sensors adapted for detecting the parameters and encoding the detected parameters onto a first light beam;
- a first optic fiber adapted for carrying the first light beam;
- a first optical beam splitter coupled to the first optic fiber, said first beam splitter adapted to receive as an input the first light beam and generate second and third optical beam outputs derived from the first light beam where the second beam has a polarization that is substantially different from the polarization of the third beam;
- second and third optic fibers that receive the second and third beam outputs, respectively, the second fiber transmitting the second beam output to an optical receiver that is geographically remote from the optical beam splitter;
- an optical polarization rotator that receives the third light beam from the optical beam splitter and generates a fourth light beam that has its polarization axes rotated substantially 45 degrees relative to the third light beam;
- a second optical beam splitter receiving the fourth light beam as an input and generating fifth and sixth output light beams carried by respective optic fibers to the optical receiver, where the fifth beam has a polarization that is substantially different from the polarization of the sixth beam.
A method for recovering optical signals carried by optical fibers that have at least one region intermediate a signal encoding source and an optical receiver that is subjected to physical vibration resulting in undesired polarization changes in the light beams carried by the optical fibers, the method comprising the steps of:
- generating, at the signal encoding source end of the optical fibers, 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;
- transmitting the first and second light beams from the signal encoding source end of the optical fibers respectively on first and second fibers, the first and second fibers subjected to said physical vibration, whereby benefits of polarization diversity are obtained at the optical receiver while minimizing degradation of signal recovery by the optical receiver due to the adverse polarization changes caused by vibration of the first and second optic fibers.
Dependencies are inferred from the claim text.