Resonator Fiber Optic Gyroscope Reference Ring Eliminates Temperature Control
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Solution Overview
Problem
Current resonator fiber optic gyroscope designs face challenges with rotation sensing errors due to beam beating and require temperature control for optical filters, leading to increased power dissipation and cost.
Innovation Solution
Incorporating a second ring resonator made of the same material as the rotation rate sensing ring, which automatically tracks shifts in resonant frequencies, eliminating the need for temperature control and large optical phase modulators, and using sideband heterodyne detection to modulate optical beams directly through the optical filter cavity onto the gyro resonator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical filters are used to clean up phase noise on slave lasers, then phase noise is reduced and gyro performance is improved, but temperature control is required to track resonant frequencies, leading to increased power dissipation and cost
Solution Approach 1:
The reference ring resonator automatically tracks the resonant frequency of the sensing coil through self-service mechanisms. By using the same fiber coil material and construction methods, the reference resonator's resonant frequency naturally follows the sensing coil's frequency shifts due to temperature and environmental changes, eliminating the need for active temperature control systems
Solution Approach 2:
The reference ring resonator is constructed using the same fiber optic material and winding techniques as the sensing coil, ensuring homogeneous material properties. This homogeneity causes both resonators to respond identically to temperature changes, allowing the reference to track the sensing coil's resonant frequency without additional control mechanisms
2Stability of the object's composition
If a master laser co-propagates with slave laser beams for frequency stabilization, then laser frequency stability is improved, but beam beating occurs causing rotation sensing errors
Solution Approach 1:
The system segments the laser stabilization function from the rotation sensing function. The master laser stabilizes the slave lasers through optical phase lock loops, while the reference ring resonator separately provides the frequency reference for rotation sensing. This segmentation prevents the master and slave beams from co-propagating in the same sensing path, eliminating beam beating errors
Solution Approach 2:
The reference ring resonator acts as an intermediary that provides frequency reference without direct beam interaction. Instead of having master and slave beams co-propagate and interact, the reference resonator mediates the frequency stabilization process through separate optical paths, allowing frequency locking without beam beating
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
This approach reduces power consumption and cost while maintaining accurate rotation rate measurements by naturally tracking resonant frequency shifts and minimizing optical noise, enhancing the performance and efficiency of the fiber optic gyroscope.
Implementation Method 1
a first optical beam and a second optical beam circulate within the first fiber optic ring resonator in opposite directions; a first optical beam and a second optical beam circulate within the second fiber optic ring
Implementation Method 2
lock the frequency of the first laser source using a first feedback signal produced by a first servo; lock the frequency of the second laser source using a second feedback signal produced by a second servo; first resonant frequency of the second fiber optic ring resonator locked-on to by the first optical beam, and a second resonant frequency of the second fiber optic ring resonator locked-on to by the second optical beam
Implementation Method 3
a first servo loop coupled to the first fiber optic ring resonator and the second fiber optic ring resonator, wherein the first servo loop controls the first laser light source as a function of a first portion of the first optical beam that has circulated through the first fiber optic ring resonator
Data Source
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Figure 1A
Figure 1B
AI summary
Systems and methods for fiber optic gyroscopes are provided. In one embodiment, a resonator fiber optic gyroscope (100) comprises: first and second laser sources (110,112) producing first and second optical beams (101,102); a first resonator (120) having a hub comprising a hub material, wherein the first and second optical beams circulate within the first resonator in opposite directions; a second resonator (140) having a hub comprising the hub material, wherein the first and second optical beams circulate within the second resonator in opposite directions; first and second servo loops (130,150) ; the first loop controls the first laser source based on a beam that has circulated through the first resonator and a beam that has circulated through the second resonator; the second servo loop controls the second laser source based on a beam that has circulated through the first resonator and a beam that has circulated through the second resonator; and a rotation rate detection circuit.