SBS Ring Laser Gyroscope Eliminates Dither Motor
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Solution Overview
Problem
Conventional HeNe ring laser gyroscopes are unsuitable for thermally extreme, high shock, and high vibration applications due to the need for fragile dither motors to prevent resonance frequency degeneracy, which are not robust enough for demanding environments.
Innovation Solution
A ring laser gyroscope utilizing stimulated Brillouin scattering (SBS) to generate two optical beams at different frequencies, eliminating the need for dither motors by using a rigid optical waveguide resonator with no moving parts, allowing for robust operation in extreme conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dither motor is used to prevent resonance frequency degeneracy in conventional RLGs, then the gyro can operate at small rates, but the device becomes fragile and unsuitable for high shock and vibration applications
Solution Approach 1:
The patent replaces the mechanical dither motor system with an all-optical solution using stimulated Brillouin scattering. The SBS effect generates two optical beams at different frequencies that propagate in opposite directions through the waveguide, eliminating the need for mechanical moving parts while maintaining the ability to measure rotation rates without lock-in effects.
Solution Approach 2:
The invention extracts and eliminates the dither motor component from the gyroscope system entirely. By using the SBS effect to create frequency-separated counter-propagating beams, the system removes the fragile mechanical elements while preserving the essential function of preventing resonance frequency degeneracy at small rotation rates.
2Adaptability or versatility
If conventional HeNe ring laser gyroscopes are used for navigation, then they provide good performance, but they fail in thermally extreme and high shock applications due to fragile moving parts
Solution Approach 1:
The patent replaces the mechanical components of conventional HeNe RLGs with an integrated photonic waveguide system that uses stimulated Brillouin scattering. This solid-state, all-optical implementation eliminates fragile moving parts while extending operational capability to thermally extreme and high shock environments through monolithic integration on a silicon substrate.
Solution Approach 2:
The invention uses a silicon substrate with integrated optical waveguides, combining materials and structures to create a robust platform that can withstand extreme thermal and mechanical conditions while maintaining precise rotation measurement capability.
3Reliability
If a rigid optical waveguide resonator with no moving parts is used, then the gyro becomes robust for extreme conditions, but conventional RLG lock-in issues must be avoided through alternative mechanisms
Solution Approach 1:
The patent changes the frequency parameter of the optical beams by utilizing stimulated Brillouin scattering to generate two distinct frequency components. This frequency separation prevents the resonance frequencies from becoming degenerate, allowing accurate rotation measurement without requiring a dither motor while maintaining robustness through the rigid waveguide structure.
Solution Approach 2:
The SBS-based system is self-sustaining, generating its own counter-propagating beams with different frequencies through the nonlinear optical interaction in the waveguide. This self-service mechanism eliminates the need for external dither motors while maintaining the ability to operate at small rotation rates without lock-in 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 SBS-based ring laser gyroscope provides high performance without fragile moving parts, enabling accurate rotation measurement in thermally extreme, high shock, and high vibration environments, while avoiding lock-in issues and requiring no dither motor, thus enhancing reliability and durability.
Implementation Method 1
A first optical gain curve is stimulated at a first Stokes wave frequency downshifted by a Brillouin Stokes frequency from the pump frequency as the optical pump beam propagates through the optical ring resonator
Implementation Method 2
A second optical gain curve is stimulated at a second Stokes wave frequency downshifted by twice the Brillouin Stokes frequency from the pump frequency by the first order SBS beam
Implementation Method 3
an optical ring resonator having a first optical coupling region and a second optical coupling region
Data Source
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AI summary
A ring laser gyroscope is provided. The ring laser gyroscope includes an optical ring resonator, an optical source to provide a pump beam at a pump frequency, a beat detector, and an optical clock detector. The pump beam is coupled to the optical ring resonator in the first direction and stimulates a first optical gain curve at a first stokes wave frequency downshifted by a Brillouin stokes frequency from the pump frequency. A first order stimulated Brillouin scattering (SBS) beam propagates in the second direction and a second order SBS beam propagates in the first direction. The beat detector produces an optical beat signal that varies as a function of a frequency difference between the first order SBS beam and the second order SBS beam. The optical clock detector generates a reference frequency signal based on two co-propagating beams.