Ring Laser Gyroscope With Coupled Resonator SBS
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Solution Overview
Problem
Conventional ring laser gyroscopes require fragile moving parts for dither motors to prevent resonance frequency degeneracy, making them unsuitable for thermally extreme, high shock, and high vibration applications, and Stimulated Brillouin Scattering (SBS) gyroscopes have high pump power requirements due to inefficiencies in converting pump laser light to Brillouin-shifted sensing frequency.
Innovation Solution
A ring laser gyroscope design incorporating a primary-optical-ring resonator and a secondary-optical-ring resonator, where the pump field stimulates first and second order SBS fields, allowing for efficient optical power coupling and reduced noise, eliminating the need for moving parts and minimizing pump power requirements by using a single pump laser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RLGs use dither motors to prevent resonance frequency degeneracy, then rotation measurement reliability is improved, but device complexity and fragility increase due to moving parts
Solution Approach 1:
The patent removes the dither motor and its associated moving parts from the RLG system. Instead of mechanically dithering the resonator to prevent frequency degeneracy, the invention uses optical field-based solutions within the resonator to achieve the same functional outcome without mechanical components.
Solution Approach 2:
The patent replaces the mechanical dither motor system with an optical field-based control mechanism. The resonator uses optical coupling and field distribution to prevent frequency degeneracy without requiring mechanical motion, thereby eliminating fragile moving parts while maintaining measurement reliability.
2Device complexity
If SBS gyroscopes use single pump laser to reduce device complexity, then device complexity is reduced, but pump power requirements increase due to conversion inefficiency
Solution Approach 1:
The patent optimizes the resonator design parameters including coupling coefficients, resonator length, and mode matching to maximize the efficiency of pump laser to Brillouin-shifted light conversion. By carefully controlling the optical coupling between modes and adjusting resonator parameters, the system achieves high conversion efficiency with a single pump laser, reducing both device complexity and power requirements.
3Measurement precision
If SBS gyroscopes use two pump lasers to generate counter propagating SBS fields, then rotation sensing performance is improved, but device complexity and power requirements increase
Solution Approach 1:
The patent makes the single pump laser perform multiple functions: it generates both the clockwise and counter-clockwise propagating optical fields needed for rotation sensing. Through careful resonator design and optical coupling, the single pump source creates the necessary counter-propagating SBS fields that would traditionally require two separate lasers, thereby maintaining measurement precision while reducing device complexity.
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 design achieves efficient rotation measurement without fragile moving parts and reduces pump power requirements by 10× or more, making it suitable for extreme environments and improving navigation and guidance systems.
Implementation Method 1
The pump field in the primary-optical-ring resonator stimulates a first optical gain curve at a first stokes wave frequency downshifted by a Brillouin stokes frequency from the pump frequency. The SBS gain gives rise to a frequency-shifted field propagating in the second direction.
Implementation Method 2
A first order SBS field stimulates a second optical gain curve at a second stokes wave frequency downshifted by twice the Brillouin Stokes frequency from the pump frequency. The second order SBS gain gives rise to a frequency-shifted field propagating in the first direction.
Implementation Method 3
The primary-optical-ring resonator includes at least one optical coupling region to couple optical fields into and out of the primary-optical-ring resonator. The secondary-optical-ring resonator includes at least two optical coupling regions, one of which couples optical fields into and out of the primary-optical-ring resonator, and one of which couples the pump field into and out of the secondary-optical-ring resonator.
Data Source
AI summary
A ring laser gyroscope (RLG) is provided. The RLG includes a primary resonator, a secondary resonator, and an optical source to provide a pump field. The pump field in the primary resonator stimulates an optical gain curve at a first stokes wave frequency. A first order SBS field stimulates a second optical gain curve at a second stokes wave frequency. The second order SBS gain gives rise to a frequency-shifted field propagating in the first direction. The fraction of the pump field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator is larger than the fraction of: the first order SBS field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator; and a second order SBS field that couples out of the primary resonator, through the secondary resonator, and out of the secondary resonator.