Method and apparatus for the elimination of polarization fading in interferometeric sensing systems
AssigneeSercel
InventorsJohn Luscombe, John Maida
Life of this patent
Estimating the term…
Abstract
In an interferometric sensing apparatus, a scrambler is positioned in front of a polarizer, followed by a detector. In that way, although the two beams remain orthogonal to each other, they are continuously rotated, relative to the polarizer. In some positions, both beams pass through the polarizer and interfere, thus eliminating polarization fading. The signal is amplitude modulated at the rotation frequency of the scrambler, but this modulation is removed by low pass filtering.
Claims5
A system to eliminate polarization fading comprising:
- a. a scrambler adapted to receive a light signal with substantially orthogonal polarization and to rotate the light signal at a selected frequency;
- and
- b. a polarizer adapted to receive the rotating light signal from the scrambler to develop detectable polarized light from the rotating light signal.
A method of eliminating polarization fading in an interferometric sensing apparatus, the apparatus having a light source, a sensing apparatus, and a light detector, the method comprising the steps of:
- a. receiving light from the sensing apparatus;
- b. rotating the received light at a selected frequency to develop a rotating beam;
- and
- c. polarizing the rotating beam to develop a detectable interference signal.
Dependencies are inferred from the claim text.