Wavelength Beam Combining with Nested External-Cavity Laser Modules
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Solution Overview
Problem
There is a demand for enhancing the optical output power and power density of laser beams combined using wavelength beam combining techniques, as existing methods face limitations in increasing the number of laser modules without increasing the device size or compromising beam quality.
Innovation Solution
A light source device comprising multiple external-cavity laser modules with different peak wavelengths and a beam combiner that allows laser beams to be incident at different angles, with varying distances from the beam combiner, enabling efficient coaxial combination and increased optical output power without expanding the device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of laser modules is increased to enhance optical output power, then the optical output power is improved, but the device size increases
Solution Approach 1:
The patent arranges laser modules at different distances from the beam combiner along the optical axis, utilizing the longitudinal dimension to accommodate multiple modules without increasing lateral device footprint. This dimensional transition allows dense packing of multiple laser modules while maintaining their individual beam paths and achieving high optical output power in a compact configuration.
Solution Approach 2:
The patent employs a nested arrangement where laser modules are positioned at different depths along the optical axis, with some modules located closer to the beam combiner and others farther away. This nesting strategy allows multiple laser modules to be integrated within a compact longitudinal space, increasing optical output power without proportionally increasing device volume.
2Device complexity
If laser modules are arranged at the same distance from the beam combiner, then the structure is simplified, but the beam quality and combination efficiency deteriorate
Solution Approach 1:
The patent applies different arrangement distances for different laser modules based on their specific wavelengths and beam characteristics. Each laser module is positioned at an optimized distance from the beam combiner to ensure proper beam alignment and quality, rather than using a uniform arrangement. This local optimization maintains high beam quality while managing structural complexity.
Solution Approach 2:
The patent varies the distance parameter of laser modules from the beam combiner to optimize beam combination efficiency and quality. By adjusting this spatial parameter for different modules, the system achieves superior beam quality and combination efficiency, accepting increased structural complexity as a necessary trade-off for performance.
3Productivity
If laser modules are arranged at different distances from the beam combiner, then the beam combination efficiency is improved, but the alignment precision becomes more difficult
Solution Approach 1:
The patent employs preliminary alignment procedures where laser modules are positioned and adjusted before final operation. The different arrangement distances are pre-calculated and pre-positioned during assembly, allowing for optimized beam combination efficiency. This preliminary action approach addresses alignment challenges by establishing precise geometric relationships before the system becomes operational.
Solution Approach 2:
The patent introduces alignment reference structures and optical reference elements as intermediaries to facilitate precise alignment of laser modules at different distances. These intermediary elements provide reference planes and alignment markers that simplify the alignment process, making it easier to achieve and maintain precise beam combination despite the varied module positions.
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 enhances the optical output power and power density of the combined laser beam, allowing for higher power density and efficient energy conversion while maintaining a compact device size.
Implementation Method 1
a diffraction grating configured to selectively reflect and transmit light of a predetermined wavelength
Implementation Method 2
a beam combiner configured to coaxially combine the plurality of laser beams to generate a wavelength-combined beam. The plurality of external-cavity laser modules are arranged so that the plurality of laser beams are incident on a same region of the beam combiner at different angles
Data Source
Figure 1~2
Figure 3~4B
Figure 5~6
AI summary
A light source device includes a plurality of external-cavity laser modules configured to emit a plurality of laser beams of different peak wavelengths, the plurality of external-cavity laser modules including at least one first laser module and at least one second laser module; and a beam combiner configured to coaxially combine the plurality of laser beams to generate a wavelength-combined beam. Each of the plurality of external-cavity laser modules includes: a collimation laser light source having a Littrow configuration, and a diffraction grating configured to selectively reflect and transmit light of a predetermined wavelength. The plurality of external-cavity laser modules are arranged so that the plurality of laser beams are incident on a same region of the beam combiner at different angles. A first distance between the first laser module and the beam combiner is different from a second distance between the second laser module and the beam combiner.