Single-Mode Semiconductor Laser Phase Control for Reproducible Wavelengths
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Solution Overview
Problem
Existing methods for producing semiconductor lasers fail to achieve true monomode operation at desired wavelengths with high reproducibility, leading to a significant proportion of rejects due to inaccurate control of laser mode selection and phase position.
Innovation Solution
A method involving the application of a multilayer structure on a semiconductor substrate, with precise positioning of an optical element relative to a lateral structure layer to control the phase position of amplified laser modes, ensuring a distance that satisfies min|d - m·λeff/2| ≤ λeff/4, thereby defining the effective refractive index and suppressing beat modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lateral structure with periodic modulation of refractive index is used for mode selection, then the number of amplifiable modes is reduced, but true monomode operation with high reproducibility cannot be achieved
Solution Approach 1:
The patent divides the laser cavity into distinct functional segments: a lateral structure region for basic mode selection and a separate optical element region for precise phase control. This segmentation allows each component to perform its specific function optimally, with the lateral structure reducing the number of amplifiable modes and the optical element precisely controlling the phase position to achieve true monomode operation with high reproducibility.
Solution Approach 2:
The patent introduces an optical element as an intermediary component between the lateral structure and the laser medium. This optical element acts as a mediator that provides precise phase control of the laser modes, enabling accurate mode selection and achieving true monomode operation. The intermediary optical element bridges the gap between the basic mode selection of the lateral structure and the requirement for precise phase control.
2Measurement precision
If the distance between optical element and lateral structure is not precisely controlled, then manufacturing is simpler, but phase position control accuracy deteriorates
Solution Approach 1:
The patent specifies predetermined distance ranges between the optical element and the lateral structure that satisfy the phase control condition. By establishing these preliminary distance specifications during the design phase, the manufacturing process can focus on achieving within-range positioning rather than requiring ultra-precise control, thus balancing measurement precision with device complexity.
Solution Approach 2:
The patent transforms the phase control problem into a geometric parameter problem by establishing specific distance relationships between components. By changing the design approach from direct phase control to distance-based phase control, the system achieves accurate phase position control through relatively simple geometric positioning, reducing the overall device complexity while maintaining high measurement precision.
3Reliability
If multiple laser modes are amplifiable, then wavelength tuning flexibility is improved, but monomode operation cannot be achieved
Solution Approach 1:
The patent creates a dynamic and adjustable optical system where the optical element can be positioned at different distances from the lateral structure, and the lateral structure itself can have varying periodic modulations. This dynamic design allows the laser to achieve true monomode operation at different wavelengths by adjusting the phase control parameters, thus maintaining wavelength tuning flexibility while ensuring monomode operation.
Solution Approach 2:
The patent establishes preliminary design parameters for the optical element and lateral structure that enable monomode operation across a range of wavelengths. By pre-configuring the distance relationships and periodic modulations to satisfy phase control conditions for multiple wavelengths, the system achieves both monomode operation reliability and wavelength tuning adaptability without requiring real-time complex adjustments.
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
Enables reliable production of semiconductor lasers operating in a monomode with precise wavelength tuning, reducing the number of amplifiable modes to exactly one, thus improving production reliability and reproducibility.
Implementation Method 1
an optical element for defining the phase position of the amplified or amplified laser modes, wherein the optical element in the longitudinal direction of the waveguide ridge has a distance d from the lateral structure layer
Implementation Method 2
The periodic modulation of the refractive index results in a strong wavelength dependence of the losses or absorption. The periodic variation of the absorption coefficient also leads to losses with a strong wavelength dependence.
Implementation Method 3
a lateral structure, at least in the material removal regions, through which a basic selection of the laser modes amplified or amplified by stimulated emission is carried out
Implementation Method 4
The fundamental operating principle of semiconductor lasers is stimulated emission. In this case, the light of a mode or oscillation mode is amplified exponentially if it lies within the gain spectrum of the laser medium
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method for manufacturing a semiconductor laser comprising the process steps of: generating a lateral structure layer, at least in the material removal areas, by which a basic selection of the laser modes enhanced or enhanceable by stimulated emission is carried out, and generating an optical element for defining the phase position of the enhanced or enhanceable laser modes, wherein the optical element is generated such that it has a distance d to an end of the lateral structure layer in the longitudinal direction of the waveguide web, which satisfies the condition where m is a natural number m∈N and λeff is the effective wavelength in the material.