Gradient Index Fiber Beam Stability
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Solution Overview
Problem
Conventional optical fiber beam delivery systems often produce non-uniform and variable beam fluxes due to inherent non-uniformities and sensitivity to fiber bending, which can alter the beam flux significantly.
Innovation Solution
The use of gradient index fibers with a cladding and core that have a refractive index difference of at least 0.04, combined with a combiner lens to overlap optical fluxes from multiple laser diodes at different angles, ensures a stable and uniform beam flux distribution, even when the fiber is bent or moved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical fibers are used for beam delivery, then the system is simple and inexpensive, but the beam flux becomes non-uniform and variable
Solution Approach 1:
The patent applies local quality by creating a gradient index core where the refractive index varies spatially (higher at the center, lower at the edges) rather than being uniform throughout. This localized variation in optical properties at different positions within the core enables uniform beam flux distribution while maintaining overall system simplicity
Solution Approach 2:
The patent changes the refractive index parameter across the core radius to resolve the contradiction. By making the refractive index a function of radial position (n(r) decreasing from center to edge), the system achieves uniform beam flux and improved reliability without significantly increasing device complexity
2Adaptability or versatility
If the fiber is bent or moved, then the system becomes more adaptable, but the beam flux becomes non-uniform
Solution Approach 1:
The gradient index structure creates local quality variations that guide light propagation paths. When the fiber is bent or moved, this localized refractive index gradient compensates for positional changes, maintaining beam flux uniformity while preserving fiber adaptability
Solution Approach 2:
The patent designs the gradient index profile in advance to compensate for potential fiber bending or movement. The refractive index gradient is configured beforehand to counteract the effects of positional changes, ensuring beam flux uniformity is maintained even when the fiber is moved or bent
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 approach results in a stable and uniform optical power distribution with minimal variation, maintaining high output power and maintaining stability across different fiber positions and orientations.
Implementation Method 1
a gradient index fiber including a cladding and a gradient index core such that a numerical aperture defined by a core/cladding refractive index difference is at least about 0.04
Implementation Method 2
a numerical aperture defined by a core/cladding refractive index difference is at least about 0.04
Data Source
AI summary
Optical illuminators comprise optical fibers having a gradient index core and a cladding selected so that a refractive index difference at a core/cladding interface provides a numerical aperture less than, greater than, or equal to a numerical aperture of the gradient index core. In some examples, a maximum refractive index difference in the gradient index core is substantially the same as, less than, or greater than the refractive index difference at the core/cladding interface. Illuminators based on such fibers are configured to produce optical beams with a laser diode or diode array, and to provide stable, approximately Gaussian optical fluxes at a fiber output surface.