Free Space Fiber Coupler With Light Stripper
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Solution Overview
Problem
Current optical systems face limitations in handling high power radiation due to low optical damage thresholds of protective coatings and adhesives, leading to thermal damage and power losses when coupling light into optical fibers, which restricts the maximum power handling capacity and causes structural issues.
Innovation Solution
The use of GRIN or multiclad fibers as couplers, combined with a light stripper and reflector, minimizes power losses and thermal damage by confining light within the core and inner cladding, and redirects stray light back into the core, while the light stripper and reflector materials manage thermal impact and alignment respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard protective coating and adhesive are used to protect optical fiber, then mechanical protection is provided, but optical damage threshold is limited due to thermal damage at high power levels
Solution Approach 1:
The patent extracts and removes the standard protective coating and adhesive materials that have low optical damage thresholds. By eliminating these thermally vulnerable components from the high-power light path, the system achieves significantly higher power handling capability without the thermal damage limitations that would otherwise constrain the maximum operating power.
Solution Approach 2:
The patent introduces specialized intermediary materials with high optical damage thresholds to replace the standard coating and adhesive. These intermediary materials are specifically selected to withstand high-power laser irradiation without thermal damage, thereby mediating between the mechanical protection requirement and the high power handling requirement.
2Strength
If adhesive material is used to couple fiber to mount, then mechanical coupling is achieved, but optical damage threshold is limited and material may melt at high temperatures
Solution Approach 1:
The patent removes the standard adhesive material from the optical path where it would be exposed to high-power laser radiation. By extracting the adhesive from the high-intensity light region, the system eliminates the thermal melting and migration problems that would otherwise limit the maximum operating power and cause structural deterioration.
Solution Approach 2:
The patent introduces high-temperature resistant intermediary materials to replace the standard adhesive in critical positions. These intermediary materials maintain mechanical coupling functionality while withstanding the thermal loads of high-power operation without melting or degrading.
3Productivity
If light is coupled into optical fiber, then light transmission is achieved, but power losses occur and thermal damage may occur to coating and adhesive
Solution Approach 1:
The patent extracts and eliminates the sources of power loss and thermal damage by removing standard coating and adhesive materials that absorb light energy. By eliminating these lossy materials from the optical path, the system achieves higher transmission efficiency with reduced power losses and minimal thermal generation.
Solution Approach 2:
The patent changes the optical and thermal parameters of the fiber assembly by using specialized materials with optimized properties. The modified fiber structure and material selection reduce absorption coefficients and improve light transmission characteristics, thereby reducing power losses while maintaining mechanical integrity.
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 significantly increases the optical power damage threshold, reduces thermal damage, and maintains structural integrity, enabling reliable high-power operation with minimal power losses and misalignment issues.
Implementation Method 1
The coupler adds necessary ruggedness to the entire receiving unit and improves coupling of light into the delivery fiber. Either GRIN fiber or multiclad fiber is used for configuring the coupler. Both these configurations are substantially different from a typical step-index fiber.
Implementation Method 2
a further volume of material with the refraction index lower than that one of the cladding is deposited over at least a part of the coupler. Such a configuration reflects at least a portion of light, which otherwise would couple out of the cladding, and, therefore, redirects most of the stray light towards the core.
Implementation Method 3
a volume of material which is operative to strip a portion of light propagating through the splice between the coupler and delivery fiber before it reaches the protective coating of the delivery fiber
Data Source
AI summary
A waveguide receiving light which propagates through free space is configured with a coupler and delivery fiber. The coupler, including a GREEN or multimode fiber, has a protective coating and so does the delivery fiber. Upon splicing of the coupler to the delivery fiber, the protective coatings of the respective coupler and delivery fiber are spaced apart exposing thus end regions of the respective coupler and fiber. The exposed regions are covered by a light stripper made of material having a refractive index which is substantially the same as or greater than that one of outer claddings. Accordingly, the light stripper minimizes the amount of light capable of coupling into the protective coatings of the respective delivery and coupler fibers enhancing thus a power handling capabilities of the waveguide.