Rhombic Optical Path Bias for Fiber-Optic Gyroscope Linearity
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Solution Overview
Problem
Fiber-optic gyroscopes face challenges in achieving high precision and cost-effectiveness while maintaining a simple structure and resistance to electromagnetic interference, particularly in the commercialization of interferometric fiber-optic gyroscope technology.
Innovation Solution
A white light interferometric fiber-optic gyroscope based on a rhombic optical path difference bias structure, utilizing a 50:50 fiber coupler network and planar lightwave circuit technology, with a laser, fiber coil, and photodetector, which introduces an optical path difference bias to enable efficient rotation rate measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mechanical gyroscope is used, then high precision measurement can be achieved, but the device has moving components and wear components leading to reduced reliability
Solution Approach 1:
The patent replaces the traditional mechanical gyroscope system with an all-fiber-optic interferometric system. The mechanical moving components are substituted by optical paths in fiber coils, where light waves interfere to measure rotation rate via the Sagnac effect. This eliminates wear components while maintaining measurement precision through optical interference patterns.
2Measurement precision
If laser gyroscope is used, then high precision can be achieved, but the system requires several thousand volts ignition voltage and ultra-high precision optical processing increasing device complexity
Solution Approach 1:
The patent uses standard optical components such as fiber couplers with 50:50 splitting ratio and conventional fiber coils that can be manufactured with standard precision tolerances. These components are replaceable and can be produced using常规 manufacturing processes, eliminating the need for ultra-high precision optical processing while maintaining measurement accuracy through the interferometric measurement principle.
3Ease of manufacture
If interferometric fiber-optic gyroscope is commercialized, then cost reduction can be achieved, but maintaining high precision while keeping structure simple presents challenges
Solution Approach 1:
The patent introduces an asymmetric optical path difference bias structure where the four fiber paths have deliberately different lengths, creating a fixed optical path difference between counter-propagating light waves. This asymmetric design enables precise rotation rate measurement by creating a measurable interference pattern shift, while using standard fiber components keeps the system cost-effective and manufacturable.
4Measurement precision
If optical path difference bias is introduced, then linear output of rotation rate signal is achieved, but the structure becomes more complex
Solution Approach 1:
The patent combines the optical path difference bias function directly into the fiber coil structure itself, rather than adding separate bias introduction components. The four fiber paths forming the rhombic structure serve dual purposes: they constitute the interferometric measurement loop and simultaneously provide the required optical path difference bias. This integration maintains structural simplicity while achieving linear rotation rate signal output.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides an all-fiber structure with high-speed algorithm demodulation, linear output, low system cost, and resistance to electromagnetic interference, enhancing the stability and precision of the gyroscope.
Implementation Method 1
the fiber-optic gyroscope has no moving component and wear component, is an all-solid-state instrument and has the advantages of low cost, long service life
Implementation Method 2
the lengths of the first fiber, the second fiber, the third fiber and the fourth fiber are inconsistent to introduce an optical path difference bias d
Implementation Method 3
the photodetector is connected with the third fiber coupler through a sixth fiber
Data Source
AI summary
A white light interferometric fiber-optic gyroscope based on a rhombic optical path difference bias structure includes a laser, a rhombic optical path difference bias structure, a fiber coil and a photodetector. The white light interferometric fiber-optic gyroscope adopts an all-fiber structure to simplify the complexity of a gyroscope system and reduce the overall cost. A white light interferometric demodulation algorithm is used to realize linear output of rotation rate signals.