Low-NA Fiber Output Diode Laser Module for High-Brightness Coupling
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Solution Overview
Problem
High-power semiconductor lasers face challenges in achieving high brightness due to increased Beam Parameter Product (BPP) when using standard core optical fibers, limiting their application in high-brightness applications.
Innovation Solution
A low numerical aperture fiber output diode laser module is developed, featuring an optical lens module with fast and slow axis collimating lenses, a reflective film-coated resonant cavity, and a core optical fiber with a low numerical aperture of 0.12 and high hydroxyl value, coupled with a laser beam cutting method for the end face and an airtight transparent mirror, to enhance beam divergence and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If standard core optical fiber is used for high-power semiconductor laser output, then the output power can be achieved, but the Beam Parameter Product (BPP) increases making it difficult to achieve high brightness
Solution Approach 1:
The patent changes the numerical aperture parameter of the optical fiber from standard values (0.22 or higher) to a low numerical aperture of 0.12. This parameter change allows the fiber to maintain high power output while achieving superior beam quality with BPP less than 5.5 mm*mrad, directly resolving the contradiction between power and beam quality
Solution Approach 2:
The patent employs dynamic optical elements including adjustable collimating lenses and focusing lenses that can be positioned along the optical path. This dynamic adjustment capability allows optimization of beam parameters to match the low NA fiber characteristics, enabling high brightness output while maintaining high power
2Productivity
If laser beam cutting method is used for optic fiber end face, then cutting speed is fast and suitable for mass production, but cutting precision and surface quality may be affected
Solution Approach 1:
The patent replaces traditional mechanical grinding and polishing methods with laser beam cutting technology. The laser beam precisely ablates the fiber end face through controlled material removal, achieving both high cutting speed and acceptable surface quality suitable for mass production of optical fibers with specific端面 requirements
3Reliability
If reflective film with higher reflectivity is coated on resonant cavity, then resistance to external reflected light is improved, but electro-optical conversion efficiency may be reduced
Solution Approach 1:
The patent optimizes the reflectivity parameter of the resonant cavity coating to a specific range that balances two competing requirements: high enough reflectivity (≥20%) to withstand external reflected light and maintain laser stability, while not so high as to excessively reduce the electro-optical conversion efficiency. This parameter optimization resolves the contradiction between reliability and energy efficiency
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 results in improved beam quality, expanded application to larger uses such as laser welding and metal 3D printing, with a beam parameter product 55% that of standard fibers, and increased durability and resistance to external light, achieving electro-optical conversion efficiency greater than 50%.
Implementation Method 1
an optical lens module, which arranged inside the case for collimating the light beams, and then converging into a convergent light beam
Implementation Method 2
collimating the light beams, and then converging into a convergent light beam in a space of the module
Implementation Method 3
the resonant cavity of the laser chip is coated with a reflective film with a reflectivity ≥20% for withstanding the higher external reflected light
Implementation Method 4
the end face of the optic fiber adopts laser beam cutting method
Data Source
AI summary
A low numerical aperture fiber output diode laser module, which having several independent diode lasers, and collimated and converged the light beam, for the coupling the light to the core optical fiber with a core diameter of 105 um and a numerical aperture of 0.12. Compared with general products with a numerical aperture of 0.22, the light output angle is reduced to 55%, and use a general blue laser diode for verification. Use an optical software for facilitating the design and optimization of the parameters of the optical lens module.