Stitched Waveguide for Fiber-Optic Gyroscope
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Solution Overview
Problem
Fiber optic gyroscopes using LiNbO3 waveguides experience ionic migration in non-atmospheric environments, leading to corruption of electro-optic modulation and inaccurate rotational rate measurements.
Innovation Solution
The use of Titanium-diffused waveguide sections in conjunction with proton-exchanged LiNbO3 waveguide sections, stitched together to maintain high polarization and stability, mitigates ionic migration by isolating areas susceptible to electric fields and preserving accurate phase modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If proton-exchanged LiNbO3 waveguides are used for electro-optic modulation, then phase modulation capability is improved, but ionic migration occurs in non-atmospheric conditions corrupting the modulation
Solution Approach 1:
The waveguide is divided into multiple sections with different structures: proton-exchanged sections for high phase modulation capability and titanium-diffused sections for ionic migration resistance. This segmentation allows each section to perform its specialized function, resolving the contradiction between modulation accuracy and operational stability.
Solution Approach 2:
Different regions of the waveguide are given different local properties: proton-exchanged regions provide high electro-optic modulation, while titanium-diffused regions provide resistance to ionic migration. This local differentiation allows the waveguide to simultaneously achieve both phase modulation accuracy and reliability in vacuum conditions.
2Reliability
If titanium-diffused waveguide sections are used to prevent ionic migration, then operational stability is improved, but phase modulation capability is reduced
Solution Approach 1:
The waveguide is segmented into titanium-diffused sections that provide ionic migration resistance and proton-exchanged sections that provide phase modulation capability. By distributing these functions across different segments, the system achieves both reliability and measurement precision.
Solution Approach 2:
The patent combines titanium-diffused waveguide sections and proton-exchanged waveguide sections into a single integrated structure. This merging allows the system to simultaneously exhibit both ionic migration resistance and high phase modulation capability that neither section could achieve alone.
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 configuration ensures stable and accurate rotational data acquisition in non-atmospheric conditions by preventing ionic migration-induced distortions, maintaining high polarization and phase modulation integrity.
Implementation Method 1
a first section of waveguide within a Lithium crystalline structure that is exposed to an electrical field, the first section of waveguide being a Titanium-diffused waveguide region; a second section of waveguide within the Lithium crystalline structure that is not within the first section of the waveguide, the second section of waveguide being a proton-exchange waveguide region
Implementation Method 2
Modulation of the counter propagating light beams is accomplished by applying a voltage across a portion of the waveguide, which in turn changes the refractive index of the LiNbO3 material. This effect enables phase modulation, φ(t), of the electromagnetic light wave transiting the waveguide.
Implementation Method 3
When the coil is undergoing rotation, a light beam traveling in the direction of rotation will experience a longer path to the other end of the fiber loop than the light beam traveling against the rotation. This is known as the Sagnac effect. As the beams exit the fiber they are combined. The phase shift between the counter-rotating light beams due to the Sagnac effect is a function of the rotational rate of the coil.
Implementation Method 4
a stitch coupling the first section of waveguide to the second section of waveguide
Data Source
AI summary
Methods and systems for improved fiber optic gyroscopes for operation in non-atmospheric environments are provided. In one embodiment, an integrated optical circuit for an interferometer subject to non-atmospheric conditions comprises: a first section of waveguide within a Lithium crystalline structure that is exposed to an electrical field, the first section of waveguide being a Titanium-diffused waveguide region; a second section of waveguide within the Lithium crystalline structure that is not within the first section of the waveguide, the second section of waveguide being a proton-exchange waveguide region; a stitch coupling the first section of waveguide to the second section of waveguide; and a third section of waveguide configured to combine reciprocal light beams to produce an interference pattern, wherein at least one of the reciprocal light beams pass through the first section of waveguide and the second section of waveguide prior to producing the interference pattern.