Optical Depolarizer Using Birefringent Crystals and Delayer
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Solution Overview
Problem
Conventional optical depolarizers are unsuitable for depolarizing quasi-monochromatic light sources due to their high cost and large volume, as they require long birefringent crystals, and struggle with depolarizing light sources with relatively long coherent lengths, limiting their application scope.
Innovation Solution
An optical depolarizer is designed with a combination of a light-combining isolation module and a depolarization module, incorporating a first and second birefringent crystal, along with a delayer, to achieve depolarization of Raman pump light sources, reducing the length and cost of birefringent crystals needed by optimizing the optic axis angles and using a delayer to create the necessary phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical depolarizers use long birefringent crystals to depolarize light, then depolarization effectiveness is improved, but device volume and cost increase
Solution Approach 1:
The patent divides the depolarization function into two separate modules: a light-combining isolation module and a depolarization module. The isolation module uses first and second birefringent crystals with specific optic axis angles (45 degrees) to separate and recombine light paths, while the depolarization module uses a third birefringent crystal with optimized dimensions to achieve the required phase difference. This segmentation allows each component to be smaller and more specialized, reducing overall device volume while maintaining depolarization effectiveness.
Solution Approach 2:
The patent introduces a delayer as an intermediary element between the light-combining isolation module and the depolarization module. This delayer acts as a mediator that adjusts the optical path length and phase relationship between light components, enabling the system to achieve the necessary phase difference for depolarization without requiring excessively long birefringent crystals. The delayer compensates for path length differences and optimizes the overall optical path.
2Reliability
If conventional optical depolarizers use long birefringent crystals to depolarize light, then depolarization effectiveness is improved, but manufacturing cost increases
Solution Approach 1:
By segmenting the system into distinct modules with specific functions, the patent enables more precise manufacturing of each component. The isolation module and depolarization module can be manufactured separately with optimized dimensions and properties, reducing the need for extremely long single-crystal structures that are difficult and expensive to produce. The modular approach also facilitates better quality control and reduces material costs.
Solution Approach 2:
The patent optimizes specific parameters of the birefringent crystals, such as the optic axis angles (set to 45 degrees for the first and second crystals) and the dimensions of the third crystal. These parameter optimizations allow the system to achieve effective depolarization with smaller, more cost-effective crystals rather than requiring excessively long crystals that would be expensive to manufacture.
3Adaptability or versatility
If conventional optical depolarizers are designed for wide spectrum light sources, then adaptability is improved, but they fail to depolarize quasi-monochromatic light sources with long coherent lengths
Solution Approach 1:
The patent employs a dynamic design where the delayer can be adjusted to compensate for the coherent length of different light sources. The delayer's optical path length can be tuned to match the specific coherent length requirements of quasi-monochromatic light sources, enabling effective depolarization across different light source types without requiring multiple fixed configurations.
Solution Approach 2:
The patent optimizes the optical path length difference between light components by adjusting the delayer's parameters. This allows the system to achieve the necessary phase difference for depolarization in quasi-monochromatic light sources with long coherent lengths. The optimized path length difference ensures that the phase relationship between orthogonal polarization components is sufficiently different to achieve effective depolarization.
4Reliability
If the optical path difference between light components is increased to depolarize light with long coherent lengths, then depolarization effectiveness is improved, but device complexity increases
Solution Approach 1:
The delayer serves as an intermediary element that efficiently manages the optical path difference requirement. Rather than using excessively long birefringent crystals or complex multi-crystal arrangements, the delayer acts as a mediator that introduces the necessary phase difference through a simple additional optical path. This approach achieves the required depolarization effectiveness without significantly increasing 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 solution enables efficient depolarization of Raman pump light sources with a compact and cost-effective design, integrating beam combining, isolating, and depolarizing functions, suitable for a wide range of light sources, including those with long coherent lengths.
Implementation Method 1
A Lyot depolarizer includes two segments of birefringent crystals or birefringent optical fibers. In the case of birefringent crystals, the Lyot depolarizer shown in FIG. 1 has a first birefringent crystal 11 and a second birefringent crystal 12
Implementation Method 2
a delayer, wherein the delayer disposed between the light-splitting component and the light-combining component, and wherein the delayer disposed on an emitting optical path of the light-splitting component
Data Source
AI summary
Methods, systems, and apparatus, for optical depolarization. One optical depolarizer includes a light-combining module comprising a birefringent prism, wherein an optic axis of a first crystal of the birefringent prism forms a 90° angle with an optic axis of a second crystal of the birefringent prism; and a depolarization module, wherein the depolarization module is disposed at a light emitting end of the light-combining module, the depolarization module comprising a light splitting component and a light-combining component disposed at an emitting end of the light-splitting component, and a delayer disposed between the light-splitting component and the light-combining component, wherein the delayer is disposed on an emitting optical path of the light-splitting component.