Multi-Clad Optical Combiner for Return Light Confinement
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Solution Overview
Problem
In existing laser systems, return light can enter the cladding of input optical fibers, leading to absorption by the covering layer, which increases the temperature and reduces reliability.
Innovation Solution
The optical combiner features a multi-clad structure for the input optical fibers, with a third cladding surrounding the second cladding, guiding return light within this area and preventing it from propagating outside, thus reducing heat absorption and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If return light enters the cladding of input optical fibers, then the light can be absorbed by the covering layer, but the temperature increases and reliability decreases
Solution Approach 1:
The cladding is segmented into multiple layers (first cladding, second cladding, third cladding) with different refractive indices. This segmentation creates distinct optical zones that guide return light through total internal reflection at the interfaces, preventing it from reaching the covering layer and causing temperature increase.
Solution Approach 2:
Each cladding layer is assigned a specific refractive index property: the first cladding has a lower refractive index than the core, the second cladding has an even lower refractive index, and the third cladding has the lowest refractive index. This local quality differentiation creates optimal conditions for guiding return light away from the covering layer.
2Reliability
If a multi-clad structure is implemented, then return light can be guided within the third cladding, but the device complexity increases
Solution Approach 1:
The cladding layers are nested concentrically around the core, with the first cladding surrounding the core, the second cladding surrounding the first cladding, and the third cladding surrounding the second cladding. This nested structure efficiently guides return light through multiple total internal reflection interfaces while maintaining a compact, integrated fiber design.
Solution Approach 2:
The optical fiber uses a composite structure with multiple cladding layers made of materials having different refractive indices. This composite approach creates enhanced optical confinement and return light management capabilities that would not be achievable with a single-material cladding.
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 effectively suppresses the increase in temperature due to light absorption by dust or other external factors, thereby enhancing the reliability of the laser system.
Implementation Method 1
a third cladding surrounding the second cladding and having a refractive index lower than the refractive index of the second cladding... the return light is easily guided in this area
Implementation Method 2
a first cladding surrounding the core and having a refractive index lower than a refractive index of the core, a second cladding surrounding the first cladding and having a refractive index lower than the refractive index of the first cladding
Data Source
AI summary
An optical combiner includes input optical fibers and a bridge fiber. The input optical fibers each includes a core, a first cladding surrounding the core and having a refractive index lower than a refractive index of the core, a second cladding surrounding the first cladding and having a refractive index lower than the refractive index of the first cladding, and a third cladding surrounding the second cladding and having a refractive index lower than the refractive index of the second cladding. The bridge fiber has an incident surface optically coupled to the core of each of the input optical fibers and an emitting surface that emits light obtained by multiplexing the light incident from each of the input optical fibers.