Ring Optical Resonator Gyroscope Temperature Compensation
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Solution Overview
Problem
Existing ring optical resonator gyroscopes face challenges in accurately determining rotation speed due to influences from temperature variations and high measurement noise, which affect the precision and reliability of the measurements.
Innovation Solution
A gyroscope design incorporating a resonant ring waveguide with four ports, an adjustable laser source, and electronic circuits to calculate power differences between optical signals, allowing for precise determination of rotation speed by adjusting the resonance wavelength and reducing noise through modulated signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a ring optical resonator is used to determine rotation speed, then the measurement capability is provided, but temperature variations influence the calculation accuracy of rotation speed
Solution Approach 1:
The patent introduces a second waveguide as an intermediary reference path that does not form a complete resonator. This reference waveguide experiences the same temperature variations as the ring resonator but does not exhibit resonance effects, allowing the system to distinguish between temperature-induced phase shifts and rotation-induced phase shifts by comparing the two paths
Solution Approach 2:
The system uses feedback by continuously comparing the optical signals from the ring resonator path and the reference waveguide path. The difference between these paths isolates the rotation effect from temperature effects, providing temperature-compensated rotation measurement through continuous signal comparison
2Measurement precision
If a ring optical resonator is used to determine rotation speed, then the measurement capability is provided, but measurement noise is high
Solution Approach 1:
The reference waveguide serves as an intermediary that carries a signal experiencing the same environmental conditions (temperature, vibrations) as the ring resonator signal but without the resonance enhancement. By subtracting this reference signal from the resonator signal, common-mode noise is rejected while preserving the rotation-induced phase difference
Solution Approach 2:
The system employs periodic modulation of the optical signal and synchronous detection to distinguish the rotation signal from random noise. The Sagnac effect produces a periodic phase modulation at the rotation frequency, which can be extracted through lock-in detection techniques that reject noise at other frequencies
3Device complexity
If resonance wavelength is fixed, then the device structure is simple, but temperature variations affect the resonance wavelength and reduce measurement accuracy
Solution Approach 1:
The patent implements dynamic wavelength tuning capability where the laser source wavelength can be adjusted to track the resonance wavelength of the ring resonator. This dynamic adaptation allows the system to maintain resonance conditions despite temperature-induced wavelength shifts, preserving measurement accuracy without requiring a completely fixed structure
Solution Approach 2:
The system changes the operating wavelength parameter dynamically to follow the resonance wavelength of the ring resonator. By adjusting the laser wavelength to match the resonator's resonance wavelength at any given temperature, the system maintains optimal measurement conditions while compensating for thermal effects
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 solution enhances the accuracy of rotation speed measurement by minimizing the impact of temperature variations and decreasing noise, resulting in improved precision and reliability compared to traditional gyroscopes.
Implementation Method 1
Gyroscopes comprising a ring optical resonator are known. In such gyroscopes, when the ring optical resonator is not rotating around its axis and an optical signal propagates through the resonator, the resonator exhibits resonance wavelengths, the interval between two successive resonant wavelengths being constant and commonly called free spectral range (FSR). Considering a fixed-order resonance, with resonance wavelength at rest λR, when the ring optical resonator is rotating around its axis, an optical signal that is propagating in the resonator in the same direction as the rotation experiences an increase of the resonance wavelength with respect to the wavelength at rest λR, and an optical signal that is propagating in the resonator in the opposite direction to the rotation experiences a decrease of the resonance wavelength with respect to the wavelength at rest λR.
Implementation Method 2
when the ring optical resonator is not rotating around its axis and an optical signal propagates through the resonator, the resonator exhibits resonance wavelengths, the interval between two successive resonant wavelengths being constant and commonly called free spectral range (FSR)
Data Source
AI summary
A device includes an optical resonator having four ports including a first port, a second port, a third port, and a fourth port. A first electronic circuit is configured to calculate a first information representative of a power difference between optical signals supplied by two of the four ports. A method of operating a device is also disclosed.