System for detecting polarization maintaining optical fiber beat length

Abstract

The present invention discloses a detection system for detecting beat length of polarization-holding optic fibre. Said system includes the following several portions: wide-spectrum light source, fibre polarizer, Michelson interferometer, photoelectric detector, preamplification circuit, phase-locked amplifier, signal generator, computer and beat length detection device, etc. Besides, said invention also provides the working principle of said detection system and its operation method and steps.

Description

technical field [0001] The invention relates to a beat length detection system for measuring the measured polarization maintaining optical fiber. The beat length detection system is composed of a hardware part and a software part. Background technique [0002] Polarization-maintaining fiber uses the shape birefringence or stress birefringence of the waveguide to maintain polarization. Stress is now widely used to achieve birefringence, that is, an additional material with a thermal expansion coefficient larger than quartz is used to generate stress in the optical fiber. When making a strained polarization-maintaining fiber, a fiber preform is made by placing two highly doped silica rods (usually boron, phosphorus, or aluminum) on either side of the core. The fiber is drawn into an optical fiber at high temperature. After the fiber is drawn, the two highly doped rods shrink when cooling, but their heat shrinkage is affected by the surrounding quartz, so that the highly doped...

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Problems solved by technology

This method has low cost of measuring instruments and simple measurement method, but the minimum value of the beat length that can be measured is affected by the magnetic gap width of the applied magnetic field

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