Microwave-over-fiber resonant system for angular velocity measurement
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Solution Overview
Problem
Conventional optical gyroscopes face challenges in achieving high precision angular velocity measurement due to latching effects, high costs, and susceptibility to temperature and vibration errors, with interferometric fiber optic gyroscopes having low accuracy and resonant fiber optic gyroscopes requiring improved practicality.
Innovation Solution
A polarization-maintaining full-reciprocity bidirectional microwave-over-fiber resonant system is developed, incorporating a bidirectional optical amplifier, narrowband optical filter, photoelectric intensity modulators, optical couplers, fiber sensing rings, and microwave filtering units to create clockwise and counterclockwise regenerative mode-locked structures, enabling stable microwave oscillations for accurate angular velocity detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser gyroscope is used to achieve high accuracy, then measurement precision is improved, but latching effect occurs and cost increases
Solution Approach 1:
The patent replaces the conventional laser gyroscope system with a microwave-over-fiber resonant system. Instead of using optical resonance in a laser cavity, the invention uses microwave resonance coupled with fiber optic technology. This substitution eliminates the latching effect inherent in laser gyroscopes while maintaining high measurement precision through microwave frequency difference detection between clockwise and counterclockwise resonant modes.
Solution Approach 2:
The patent changes the operating parameter from optical frequency (laser) to microwave frequency. By operating at microwave frequencies rather than optical frequencies, the system avoids the latching effect that plagues laser gyroscopes. The microwave resonant system detects angular velocity through frequency difference measurement, achieving high accuracy without the reliability issues of conventional laser gyroscopes.
2Device complexity
If interferometric fiber optic gyroscopes are used, then device complexity is reduced, but gyroscopic accuracy decreases due to temperature and vibration errors
Solution Approach 1:
The patent employs microwave resonance, which inherently involves oscillatory vibration at microwave frequencies. The resonant microwave system uses standing wave patterns in the fiber optic cavity, creating a highly stable oscillating field that is less susceptible to external disturbances. This vibrational resonance approach provides natural immunity to temperature and vibration errors that affect interferometric systems, while maintaining relatively simple device structure.
3Measurement precision
If resonant fiber optic gyroscopes are used to reduce interferometric noise, then measurement precision is improved, but device complexity and difficulty of operation increase
Solution Approach 1:
The patent substitutes the complex optical resonance system with a microwave resonance system implemented over fiber optics. The microwave-over-fiber approach simplifies the resonant cavity requirements and reduces the complexity of maintaining optical resonance conditions. The system achieves noise reduction through microwave frequency stability while requiring less complex device architecture and easier operation compared to conventional resonant fiber optic gyroscopes.
4Measurement precision
If bidirectional optical resonance is implemented to achieve full reciprocity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a bidirectional microwave-over-fiber resonant system where the same fiber optic cavity supports both clockwise and counterclockwise microwave modes. The system uses a single unified resonant structure that inherently provides full reciprocity by treating both directions symmetrically. This universal approach achieves high measurement precision through reciprocal frequency difference detection while avoiding the need for separate complex optical paths required in conventional bidirectional systems.
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
The system achieves high precision angular velocity measurement with improved signal-to-noise ratio and reduced temperature drift, enhancing the accuracy and practicality of optical gyroscope applications.
Implementation Method 1
The basic principle of detecting a rotational angular velocity of a carrier by the laser gyroscope and the fiber optic gyroscope is Sagnac effect. Since the phase difference or frequency difference created under the Sagnac effect is only related to the rotational angular velocity of the carrier
Implementation Method 2
a first photoelectric intensity modulator, an optical coupler, the fiber sensing ring working structure and a second photoelectric intensity modulator are connected in sequence
Data Source
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AI summary
A polarization-maintaining fully-reciprocal bi-directional optical carrier microwave resonance system and an angular velocity measurement method thereof. In the system, highly stable optical carrier microwaves are generated in a clockwise direction and a counterclockwise direction in the same resonant cavity, and are used to measure the angular velocity of rotation of a carrier apparatus. A fully reciprocal ring-shaped resonant cavity structure is used to achieve a fully reciprocal bi-directional optical resonance system. A polarization state separation technique is used to separate an optical signal into two wavelengths, and optical signals with perpendicular polarization states are transmitted in opposite directions in a sensing ring, thereby improving the measurement capability of the sensing ring. Bi-directional optical carrier microwave resonance is achieved by using a phase tracking structure and a regenerative mode locking technique. A cavity length control technique is used to lock the oscillation frequency of microwaves in one of the directions to a highly stable standard time reference source, thereby achieving a stable relative cavity length of an optical resonant cavity. The described key techniques greatly improve the signal-to-noise ratio of bi-directional oscillation difference frequency signals caused by the Sagnac effect. The system and the method are practical and have high measurement precision.