Patent ID: 6400869
Filing Date: 2002-06-04
Classification: G02B,H04B

Abstract:
An optical fiber device, comprising:a first optic fiber to transport optical energy and to exhibit optical birefringence for light polarizations along first and second polarization axes that are substantially perpendicular to said first fiber; a fiber grating formed between a first location and a second location in said first fiber to have a periodic spatial pattern that changes nonlinearly with a position along said first fiber to effectuate different relative delays in reflected optical spectral components of a common polarization of different wavelengths at different positions along said fiber grating that meet Bragg conditions and different relative delays between two reflected optical components of different light polarizations respectively along said first and second polarization axes at a common wavelength, said fiber grating operable to interact with an input optical signal traveling from said first location towards said second location in said first fiber to produce a first optical signal by reflection in a direction from said second location towards said first location; a second fiber having a first distal end coupled to said first fiber at a position to receive said first optical signal through said first location, and a second distal end coupled to said first fiber at a different position to direct said first optical signal back into said fiber grating at said second location, wherein said fiber grating operates to reflect said first optical signal to produce an output optical signal directing from said first location towards said second location; and a polarization rotator coupled in said second fiber to rotate a light polarization by about 90 degrees.