Semiconductor Laser Array Reflectance Tuning for Stable High Output
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Solution Overview
Problem
Conventional semiconductor laser arrays in WBC type processing apparatuses face challenges in achieving high output due to insufficient reflectance of the reflection film at the gain wavelength, leading to reduced laser processing efficiency.
Innovation Solution
The semiconductor laser element and array incorporate a resonator structure with specific reflection films on the non-emission and emission end surfaces, where the reflectance of the second reflection film at the gain wavelength is optimized within certain relational expressions relative to the external resonance mirror's reflectance and coupling efficiency, ensuring efficient laser oscillation and output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a reflection film is provided on the emission end surface of the semiconductor laser array, then laser light can be reflected back into the resonator structure, but the reflectance at the gain wavelength is insufficient leading to reduced output value
Solution Approach 1:
The patent applies parameter changes by precisely controlling the reflectance of the second reflection film at the gain wavelength to fall within a specific range (1% ≤ R ≤ R(Oc)×C). This optimized reflectance parameter ensures sufficient feedback into the resonator while minimizing energy loss, thereby achieving high output values in the WBC type processing apparatus.
2Reliability
If the reflectance of the second reflection film is increased to improve laser oscillation, then more light is reflected back into the resonator, but internal resonance effects increase and output stability decreases
Solution Approach 1:
The patent resolves this contradiction by optimizing the reflectance parameter of the second reflection film to a specific range (1% ≤ R ≤ R(Oc)×C). This controlled parameter change ensures sufficient light feedback for stable laser oscillation while suppressing excessive internal resonance effects, thereby achieving both reliability and stability in the laser output.
3Power
If conventional reflection films are used with fixed reflectance, then manufacturing is simplified, but the output value of the processing apparatus is insufficient for high-power laser processing
Solution Approach 1:
The patent balances power output and ease of manufacture by specifying a reflectance range (1% ≤ R ≤ R(Oc)×C) rather than a fixed value. This range-based specification allows for practical manufacturing tolerances while ensuring sufficient output values for high-power laser processing applications, making the solution both effective and manufacturable.
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 enhances the output of the laser processing apparatus by optimizing the reflectance of the reflection films, reducing internal resonance effects and stabilizing the laser output, thereby achieving higher power and efficiency in laser processing.
Implementation Method 1
a first reflection film and a second reflection film that are provided on a non-emission end surface of the resonator structure and an emission end surface of the resonator structure, respectively, and reflect the laser light
Implementation Method 2
when the resonator structure performs laser oscillation with power 1.4 times a minimum value of threshold power
Implementation Method 3
disposed in a wavelength beam combining type processing apparatus including an external resonance mirror
Data Source
AI summary
Provided is a semiconductor laser element including: a resonator structure; and a first reflection film and a second reflection film provided on a non-emission end surface of the resonator structure and an emission end surface of the resonator structure, respectively. Reflectance R of the second reflection film at a gain wavelength satisfies the following relational expression: R1≤R≤R(Oc)×C where R1 is reflectance of the second reflection film when the resonator structure performs laser oscillation with power 1.4 times a minimum value of threshold power which is minimum power for the resonator structure to perform the laser oscillation, R(Oc) is reflectance of the external resonance mirror, and C is a ratio of light, which is reflected by the external resonance mirror and is incident in the resonator structure, to light which is reflected by the external resonance mirror.