Compact Prism Beam Combiner for Multi-Wavelength Laser Systems
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Solution Overview
Problem
Existing methods for combining laser beams of different wavelengths into a single optical fiber require large spacing between fiber connectors and complex beam paths, leading to increased cost and complexity due to the need for multiple fold mirrors and broad-band reflective coatings, making it difficult to fit the beam combiner into a compact enclosure.
Innovation Solution
The use of a plurality of directing-prisms, each aligned to direct a different-wavelength laser beam onto a combining-prism, allowing the beams to exit along a common path and be focused into an output optical fiber, with all prisms being of equal dimensions and material to minimize dispersion and reduce the need for coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single combining-prism is used to combine multiple different-wavelength laser beams, then the device complexity is reduced and manufacturing is simplified, but the beams require large spacing between fiber connectors and long beam paths
Solution Approach 1:
The patent divides the beam combining function into multiple identical prism assemblies, each handling a specific wavelength band. Each assembly includes a directing-prism and a combining-prism working together to combine two beams. This segmentation allows each prism to be smaller and positioned closer to its input fibers, reducing overall beam path length while maintaining the ability to combine multiple wavelengths through cascaded stages.
2Area of stationary object
If fiber connectors are spaced closely to reduce footprint, then the enclosure size is reduced, but the beam dispersion angle requires larger distance from prism to deliver along appropriate angle
Solution Approach 1:
The patent uses fold mirrors to redirect beam paths in multiple spatial dimensions, allowing the beam path to be folded back on itself. This enables the beam to travel a longer optical path distance while maintaining a compact physical footprint. The fold mirrors effectively add dimensional complexity to the spatial arrangement, decoupling the relationship between physical enclosure size and optical path length.
3Area of stationary object
If fold mirrors are added to accommodate compact beam paths, then the enclosure footprint is reduced, but the device complexity and cost increase due to additional coatings and components
Solution Approach 1:
The patent merges the functions of beam directing and beam combining into integrated prism assemblies. Each assembly combines the functions of wavelength-specific beam direction and beam combination in a unified optical structure, eliminating the need for separate fold mirrors and reducing the total number of optical surfaces requiring coatings. This merging reduces device complexity while achieving compact footprint through optimized prism geometry and arrangement.
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 allows for a compact beam combiner design with reduced optical losses and simplified manufacturing, accommodating multiple wavelengths within a smaller footprint while maintaining high coupling efficiency and minimizing the need for additional optical components.
Implementation Method 1
Each of the plurality of directing-prisms is arranged to transmit a corresponding one of the first plurality of different-wavelength laser-beams and direct that laser-beam to the combining-prism
Implementation Method 2
a prism configured to combine beams at the angle of minimum dispersion (incidence angles at entrance and exit faces of the prism about equal) can transmit plane-polarized radiation
Implementation Method 3
The first plurality of directing-prisms and the combining-prism are configured and arranged such that the first plurality of different-wavelength laser-beams is transmitted by the combining-prism and exits the combining-prism along a common path
Implementation Method 4
a prism configured to combine beams at the angle of minimum dispersion (incidence angles at entrance and exit faces of the prism about equal) can transmit plane-polarized radiation (p-polarized with respect to the prism faces) with reflection losses less than about 1%
Implementation Method 5
the combined beams exits the combiner and is focused into an output optical fiber
Data Source
AI summary
A beam combiner for combining laser-beams of different colors along a common path includes a directing-prism for each of the laser-beams and one combining-prism. The directing-prisms are arranged to transmit the laser-beams to the combining-prism. The directing-prisms and the combining-prism are configured and arranged with respect to each other such that the directing-prism transmits the beams along the common path.