Bidirectional Microwave-Over-Fiber Gyroscope Resolving Non-Reciprocity Errors
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Solution Overview
Problem
High precision optical gyroscopes face challenges such as latching effects, high maintenance costs, low optical power utilization, temperature errors, parasitic noise, and non-reciprocity errors due to bidirectional transmission limitations, which affect their accuracy in detecting angular velocity.
Innovation Solution
A bidirectional microwave-over-fiber resonant system based on a circulator structure is employed, utilizing a broadband spectrum light source, wavelength division multiplexers, photoelectric converters, interferometer controllers, and regenerative cavities to form clockwise and counterclockwise ring resonant cavities, with a sensing ring interferometer structure to adjust polarization states and compensate for non-reciprocity errors, generating stable microwave oscillations for angular velocity measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bidirectional transmission capability is used in optical gyroscopes, then the system can achieve Sagnac effect detection, but non-reciprocity errors are introduced that reduce measurement accuracy
Solution Approach 1:
The patent introduces a circulator as an intermediary device in the optical path to separate clockwise and counterclockwise light beams. The circulator directs light in specific directions, ensuring that the reference beam and sensing beam travel through different paths, thereby eliminating non-reciprocity errors while maintaining bidirectional transmission capability for Sagnac effect detection.
Solution Approach 2:
The optical path is segmented into distinct clockwise and counterclockwise channels using wavelength division multiplexing. Different wavelengths are assigned to different transmission directions, allowing independent optimization of each path and eliminating interference between bidirectional beams, thus resolving the non-reciprocity issue.
2Measurement precision
If laser gyroscopes are used to achieve high accuracy, then angular velocity detection precision is improved, but latching effect occurs and maintenance cost increases
Solution Approach 1:
The patent replaces the mechanical rotating mirror system of traditional laser gyroscopes with an all-optical resonant cavity system. This substitution eliminates mechanical wear and latching effects while maintaining high measurement precision through optical resonance and Sagnac effect detection.
Solution Approach 2:
The system uses regenerative amplification to dramatically increase the circulating optical power in the resonant cavity, changing the light intensity parameter to enhance the Sagnac effect signal while avoiding the latching problem inherent in low-power laser gyroscopes.
3Device complexity
If interferometric fiber optic gyroscopes are used, then the system structure is simplified, but optical power utilization is low and temperature errors increase
Solution Approach 1:
The patent employs optical resonant cavities that trap and circulate light for multiple passes, creating a phase transition effect where light repeatedly traverses the sensing path. This resonant circulation dramatically increases optical power utilization efficiency while maintaining a simplified fiber optic structure.
4Volume of moving object
If resonant fiber optic gyroscopes are used, then miniaturization is facilitated, but light source requirements become excessively high
Solution Approach 1:
The patent implements a regenerative feedback mechanism where a portion of the circulating optical signal is fed back into the resonant cavity through an optical amplifier. This feedback loop allows the system to build up high circulating power from a relatively low-power light source, enabling miniaturization without excessive power requirements.
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 accuracy in detecting rotational angular velocity with improved signal-to-noise ratio and frequency stability, reaching 10−13, by eliminating temperature drift and optical parasitic noise, and enhancing the utility of optical gyroscopes for high precision applications.
Implementation Method 1
The rationale for optical gyroscopes detecting the rotation angular velocity of the carrier is Sagnac effect. The basic principle of Sagnac effect is that in a closed optical path, two light beams emitted by the same light source and transmitted in clockwise (CW) and counterclockwise (CCW) directions create different optical path differences due to carrier rotation
Implementation Method 2
Resonant light in a clockwise direction passes sequentially through the first optical coupler, the second regenerative cavity cavity-length adjuster, the second high speed photoelectric detector, the second microwave filtering and amplifying unit, and the third microwave power divider to be fed back and modulated by the first photoelectric intensity modulator, so as to constitute a clockwise regenerative mode-locked structure
Implementation Method 3
a low speed photoelectric converter... the second high speed photoelectric detector... the first high speed photoelectric detector
Implementation Method 4
a first wavelength division multiplexer, a second wavelength division multiplexer
Data Source
AI summary
A bidirectional optical-carrying microwave resonance system based on a circulator structure and a method for detecting angular velocity by said system. A high-stability optical-carrying microwave of which polarization states in forward and reverse directions are perpendicular is generated in an optical fiber ring by utilizing a regenerative mold locking technology, a cavity length control technology, and a polarization state separation technology, and the optical-carrying microwave is used for measuring a rotational angular velocity. The circulator structure is adopted and the bidirectional optical-carrying microwave resonance is achieved by means of a bidirectional regenerative mode locking technology. A reciprocal bidirectional optical-carrying microwave resonance system is achieved on the basis of a non-reciprocal error elimination technology of a wide-spectrum optical interferometer. The polarization state separation technology is adopted to achieve dual-wavelength separation of optical signals and the perpendicular polarization state is adopted for opposite transmission in a sensitive ring, so that the detection capability of the sensitive ring is improved. The cavity length control technology is adopted to lock a microwave oscillation frequency in one direction to a high-stability standard-time reference source, so that a relative cavity length of an optical resonant cavity is stabilized. The system has the characteristics of high practicability, high measurement precision and the like.