Fiber Splice Cladding Light Stripping for High-Power Beam Combiners
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Solution Overview
Problem
High power laser beams in multimode fibers cause increased sensitivity and heating due to cladding light leakage, leading to combiner failure and sensitivity to high power exposures, which existing technologies fail to adequately address.
Innovation Solution
The implementation of cladding light stripping regions secured with a polymer to a thermally conductive support, with grooves for securing the cladding light stripping regions and using transparent index-matching adhesives, to attenuate cladding light and dissipate heat effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If etching or tapering is used to couple input fiber cores, then optical coupling is achieved, but sensitivity to high beam powers increases due to cladding light leakage
Solution Approach 1:
The harmful cladding light is extracted from the fiber cladding by introducing a cladding light stripping region with a different refractive index (such as a polymer coating or exposed cladding) that causes the cladding modes to leak out of the fiber and be dissipated, thereby removing the harmful factor before it reaches the combiner
Solution Approach 2:
The cladding light that would otherwise be harmful is converted into a beneficial effect by using its leakage through the cladding light stripping region to dissipate energy in a controlled manner, transforming the harmful leakage into a protective mechanism that prevents combiner damage
2Temperature
If cladding light is stripped in the combiner, then heating is reduced, but combiner sensitivity to high power exposures increases
Solution Approach 1:
The cladding light stripping is performed preliminarily, before the light enters the combiner, by introducing a cladding light stripping region in the input fiber that removes cladding modes in advance, preventing them from causing heating or damage in the combiner
3Power
If fiber cores are optically coupled to deliver high power, then power delivery is achieved, but cladding light leakage causes heating and potential failure
Solution Approach 1:
The fiber structure is segmented into distinct functional regions: a core transmission region for high-power laser delivery, a cladding light stripping region with different refractive index for removing cladding modes, and a combiner region. This segmentation allows each region to perform its specific function without interfering with others
Solution Approach 2:
The cladding light stripping region acts as an intermediary between the input fiber core and the combiner, mediating the transition by selectively removing harmful cladding light while preserving the core transmission, thus protecting the combiner from heating effects
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 solution effectively attenuates cladding light and dissipates heat, preventing combiner damage and enhancing the system's ability to handle high power laser beams safely.
Implementation Method 1
the cladding light stripping region is embedded in a transparent index matching polymer
Implementation Method 2
the cladding light stripping region is secured with a polymer to a thermally conductive support
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Beam combining optical systems include a fiber beam combiner having multiple inputs to which output fibers of laser diode sources are spliced. Cladding light stripping regions are situated at the splices, and include exposed portions of fiber claddings that are at least partially encapsulated with an optical adhesive or a polymer. A beam combiner fiber that is optically downstream of a laser source has an exposed cladding secured to a thermally conductive support with a polymer or other material that is index matched to the exposed cladding. This construction permits attenuation of cladding light propagating toward a beam combiner from a splice.