Segmented Poled Optical Fiber Phase Modulator
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Solution Overview
Problem
Current fiber optic sensors face limitations in phase modulation due to the need for discrete components or fiber deformation, leading to drift and non-linear response, especially in inertial measurement systems like fiber optic gyroscopes.
Innovation Solution
The use of poled optical fibers with embedded electrodes to induce phase shifts via second-order optical nonlinearities, such as the Kerr effect, allowing for integral phase modulation within the fiber without coupling out the light, thereby reducing drift and non-linear response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete integrated optic components or fiber deformation methods are used for phase modulation, then phase modulation can be achieved, but drift and non-linear response occur
Solution Approach 1:
The patent merges the phase modulation function directly into the optical fiber by creating poled segments within the fiber structure itself, eliminating the need for separate discrete components. The fiber is divided into poled and unpoled segments, with the poled segments providing the phase modulation effect, thereby integrating the modulation function into the transmission medium and reducing drift and non-linear response.
Solution Approach 2:
The patent replaces mechanical fiber deformation methods with an electro-optic mechanism. By applying an electric field to the poled segments of the fiber, phase modulation is achieved through the electro-optic effect rather than mechanical deformation, eliminating the need for piezoelectric phase modulators and their associated drift issues.
2Reliability
If proton-exchanged lithium-niobate integrated optics phase modulators are used, then phase modulation is achieved, but charge migration phenomena cause drift and environmental sensitivity
Solution Approach 1:
The patent extracts the problematic ferroelectric characteristics from the modulation mechanism. Instead of using proton-exchanged lithium-niobate crystals that exhibit charge migration and ferroelectric behavior, the invention uses poled glass fiber segments that provide phase modulation through a different mechanism, eliminating charge migration phenomena and associated drift issues.
Solution Approach 2:
The patent changes the material parameters and physical state of the optical fiber. By creating poled segments within glass fiber (rather than using crystalline lithium-niobate), the invention modifies the electro-optic properties to eliminate charge migration while maintaining phase modulation capability. The poled glass segments provide the necessary nonlinearity without the ferroelectric characteristics that cause drift.
3Reliability
If light is coupled out of the fiber for modulation, then phase modulation can be implemented, but mode coupling and non-linear response occur
Solution Approach 1:
The patent merges the phase modulation function directly into the optical fiber by creating poled segments within the fiber structure itself, eliminating the need for separate discrete components. The fiber is divided into poled and unpoled segments, with the poled segments providing the phase modulation effect, thereby integrating the modulation function into the transmission medium and reducing drift and non-linear response.
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 enables higher frequency modulation with reduced drift and non-linear response, offering low cost, seamless integration, high optical damage threshold, and low dispersion, making it suitable for advanced sensing applications like inertial measurement systems.
Implementation Method 1
at least one segment of the optical fiber is poled in such a manner as to induce a phase shift in light propagating through the optical fiber in response to application of voltage to the electrode
Implementation Method 2
The use of poling to induce second-order optical nonlinearities in optical fibers, for both silicate and chalcogenide glasses
Implementation Method 3
The poling mechanism entails creating a quasi-permanent charge distribution in the glass by cooling it under a strong applied electric field
Data Source
AI summary
A fiber optical sensor and methods for sensing a physical quantity such as rotation using the same. The sensor has an optical fiber supporting propagation of light that is configured as an interferometer. One or more segments of the optical fiber, where the segments may be non-contiguous, are poled in such a manner that a phase shift in light propagating through the fiber is created in response to application of a voltage to an electrode thereby inducing an electric field across a poled segment of the fiber. A phase modulator comprising multiple poled segments is additionally described. Applying phase-shifting effects differentially across poled segments of optical fibers of an array of optical fibers may also allow for steering an optical beam.