Laser Diode Bar Array Layout for Stable Wavelength Beam Combining
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Solution Overview
Problem
The existing wavelength beam combining systems face inefficiencies due to large differences between the gain peak wavelength of laser diode bars and the lock wavelength, leading to some emitters being unable to oscillate, which reduces the overall system performance.
Innovation Solution
A wavelength beam combining system and method for manufacturing a laser diode bar array where the main axis direction of at least one laser diode bar is reversed with respect to another, aligning the wavelength distribution to ensure all emitters can oscillate within the predetermined range, thereby maximizing output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all laser diode bars are arranged with the same main axis direction, then the system structure is simple and easy to manufacture, but the gain peak wavelength difference becomes too large causing some emitters to be unable to oscillate
Solution Approach 1:
The patent applies asymmetry by reversing the main axis direction of off-angle for at least one laser diode bar relative to others. This creates an asymmetric arrangement where some bars have the same main axis direction while at least one has a reversed direction, allowing different emitters to operate at different wavelengths within the gain bandwidth, thereby enabling oscillation for all emitters while maintaining a relatively simple manufacturing process
2Reliability
If the main axis direction of off-angle is reversed for at least one laser diode bar, then all emitters can oscillate within the predetermined wavelength range, but the system structure becomes more complex
Solution Approach 1:
The patent implements a controlled asymmetric configuration where the main axis direction of off-angle is reversed for at least one laser diode bar but not necessarily all bars. This partial asymmetry is sufficient to enable all emitters to oscillate while minimizing the complexity increase compared to a completely symmetric arrangement
Solution Approach 2:
The patent applies local quality by making the main axis direction reversal specific to at least one particular laser diode bar rather than uniformly changing all bars. This localized modification allows the system to achieve the required wavelength distribution and oscillation performance for all emitters while keeping the overall system structure as simple as possible
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 ensures that all emitters in the laser diode bar array can externally resonate, enhancing the oscillation performance and output of the wavelength beam combining system by maintaining the difference between the gain peak wavelength and lock wavelength within a viable range.
Implementation Method 1
The diffraction grating diffracts the incident beams at a diffraction angle determined by a wavelength thereof, and then the beams are emitted
Implementation Method 2
The external resonance mirror is a partially transmissive mirror that reflects a part of the incident beams perpendicular to a direction of the diffraction grating
Implementation Method 3
a feedbacking between the rear mirror of the LD bar and the external resonance mirror, and an external resonance oscillation are made only for a wavelength (called a lock wavelength)
Data Source
AI summary
In a WBC system of the present disclosure, an LD bar array constituted by a plurality of LD bars is configured such that a main axis direction of an off-angle of at least one LD bar is reversed with respect to a main axis direction of an off-angle of the other LD bar. By doing so, even in the LD bar in which a wavelength distribution in a wafer exists, a difference between a designed lock wavelength and a gain peak wavelength can be kept within a range where an LD oscillation due to an external resonance is possible for all emitters in the LD bar, thereby an output in the WBC system can be maximized.