Resources Contact Us Home
Fiber optic rotation sensor utilizing high birefringence fiber and having reduced intensity type phase errors

Image Number 12 for United States Patent #4881817.

A fiber optic rotation sensor using birefringent optical fiber includes an uncorrelating element, an equalizing element and a polarizer in the common input and output fiber portions of the sensor to reduce or eliminate the intensity type phase errors caused by interference between lightwaves originally in the same polarization mode on entry to the sensor loop that cross couple into another polarization mode. In the preferred embodiment, the uncorrelating element comprises a birefringence modulator and a length of birefringent fiber. The equalizing element comprises a birefringent fiber having a splice at which the axes of birefringence of the spliced portions of the fiber are positioned at relative to each other. The preferred embodiment also advantageously includes a birefringence modulator that introduces a time-varying birefringence into the optical fiber to introduce a deterministic phase error that reduces or eliminates amplitude type phase error caused by coherent interference between field components of light that are orthogonally polarized at the input of the sensor loop and that couple to the same polarization mode within the loop.

  Recently Added Patents
Magnesium metal-air battery
Aisle barrier
Reference circuit with curvature correction using additional complementary to temperature component
Combination therapy to enhance NK cell mediated cytotoxicity
Bi-directional pattern dependent noise prediction
Electrostatic charger and image forming apparatus
Mobile device case with storage compartment
  Randomly Featured Patents
Portable car-used oil extracting and tire inflation apparatus with separately disposed oil and air pumps
Auxiliary water projector for jet propelled watercraft
Method for intercontroller communications in a safety instrumented system or a process control system
Intermediately cooled air vacuum pump with balancing of the pressures
Feeding apparatus, and image forming apparatus incorporating feeding apparatus
Internally damped blade
Semiconductor device
Method for controlling the quantity of air in a self-contained air supply system for a chassis
Microprocessor with common bus for memory and peripheral circuit having data latch generator
Apparatus and method for measuring the thickness of thin films