Fiber Optical Modulator Using Stress-Tuned Birefringence
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Solution Overview
Problem
Conventional optical modulators employing free-space or bulk optical components face challenges such as increased complexity, optical losses, and reliability constraints, which are mitigated by fiber-based optical modulators that eliminate these issues.
Innovation Solution
A fiber-based optical modulator using a birefringent fiber positioned between polarizers, where an external force is applied to modulate the birefringence, altering the polarization state of the optical beam and thereby controlling its transmittance through an output polarizer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If free-space or bulk optical components are used in optical modulators, then optical modulation function is achieved, but device complexity and optical losses increase
Solution Approach 1:
The patent replaces free-space optical components with an integrated photonic circuit implementation. The modulator uses waveguide-based optical paths instead of mechanical free-space optics, eliminating the need for separate optical benches, mirrors, and lenses. This integration substitutes mechanical/optical assembly with a solid-state photonic circuit, reducing complexity while maintaining modulation functionality.
Solution Approach 2:
The patent merges multiple optical functions into a single integrated photonic circuit. The modulator combines the optical waveguide, phase modulation elements, and beam combination paths into one monolithic device. This merging eliminates the need for separate free-space optical components and their associated alignment mechanisms, directly reducing device complexity and improving reliability.
2Reliability
If free-space or bulk optical components are used in optical modulators, then optical modulation function is achieved, but optical losses increase
Solution Approach 1:
The patent replaces free-space optical propagation with waveguide-based optical confinement. Light is guided through high-refractive-index waveguide cores that minimize scattering and absorption losses. This substitution eliminates losses associated with free-space propagation, mirror reflections, and alignment misalignments, directly reducing optical energy loss while improving reliability.
3Productivity
If free-space or bulk optical components are used in optical modulators, then optical modulation function is achieved, but inherent optical losses and reliability constraints occur
Solution Approach 1:
The patent merges the modulation function directly into the waveguide structure itself. The phase modulators are integrated alongside the optical beams within the same photonic circuit substrate. This integration eliminates the need for separate free-space modulation components, reducing the number of interfaces and potential failure points, thereby improving reliability while maintaining modulation efficiency.
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 modulator achieves efficient temporal amplitude modulation without free-space optics, enabling stable and tunable optical loss control in optical systems, including lasers, with applications in telecommunications, materials processing, and sensing.
Implementation Method 1
A fiber-based optical modulator using a birefringent fiber positioned between polarizers, where an external force is applied to modulate the birefringence, altering the polarization state of the optical beam
Implementation Method 2
an external force is applied to modulate the birefringence
Data Source
AI summary
Systems and methods for temporal amplitude modulation of an optical beam. An exemplary system may include a birefringent fiber positioned between two polarizers, or between a polarized input light source and an output polarizer. Light may enter the birefringent fiber as linearly polarized. Depending on birefringence and orientation of the birefringent fiber, the polarization state changes as the light propagates through the birefringent fiber. This changed polarization state then enters the output polarizer, for which transmission is a function of the polarization state and the relative orientation of the polarization axis. The polarization state emerging from the birefringent fiber may be changed by modulating the fiber birefringence, for example through application of an external stress. Net transmittance of the system may be varied according to a magnitude of an external force (e.g., pressure) to some or all of the birefringent fiber.