Inclined Side Faces in Semiconductor Laser Waveguide
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Solution Overview
Problem
Conventional semiconductor laser devices face challenges in achieving high-power operation with stable multiple transverse mode output due to light leakage from the optical waveguide in the transverse direction, leading to feedback and instability, especially at high current injection levels, which results in reduced yield and reliability.
Innovation Solution
A semiconductor laser device with a stacked structure featuring inclined side faces that reflect and inhibit light leakage from the optical waveguide, allowing for stable multiple transverse mode operation even at increased current injection, by positioning the active layer within the internal reflection distance of the inclined side faces, thereby reducing feedback and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If current injection level is increased to achieve high-power operation, then optical output power is improved, but light leakage from optical waveguide increases causing feedback and instability
Solution Approach 1:
The patent converts the harmful light leakage from the optical waveguide into a beneficial effect by designing the inclined side faces to reflect this leaked light back into the waveguide core, transforming what would be loss and instability into enhanced light confinement and improved operational stability at high power levels
Solution Approach 2:
The patent addresses the two-dimensional light leakage problem by introducing a three-dimensional geometric solution through inclined side faces, adding a dimensional aspect to light management that enables reflection and redirection of leaked light back into the guiding structure
2Ease of manufacture
If conventional semiconductor laser structure is used, then manufacturing simplicity is maintained, but light leakage causes feedback and mode instability
Solution Approach 1:
The patent applies the principle of curvature by replacing the conventional flat side faces with inclined surfaces, creating a geometric configuration that actively manages light propagation through reflection, thereby improving mode stability while maintaining compatibility with standard semiconductor fabrication processes
3Area of moving object
If active layer width is increased to support multiple transverse modes, then mode capacity is improved, but light leakage and feedback increase causing instability
Solution Approach 1:
The patent changes the geometric parameters of the side faces from flat to inclined, fundamentally altering the light interaction characteristics and enabling stable multiple transverse mode operation by controlling the reflection and confinement of light within the expanded active layer structure
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
The semiconductor laser device achieves high-power, long-term reliable operation with reduced optical waveguide losses and increased efficiency, enabling stable multiple transverse mode output at high current levels without the issues of light feedback and leakage.
Implementation Method 1
A pair of side faces as a pair are formed in portions of the stacked structure that ranges from part of the first conductivity-side semiconductor layer to the second conductivity-side semiconductor layer. The pair of side faces in at least part of the first conductivity-side semiconductor layer is inclined to the main surface of the substrate.
Data Source
AI summary
A semiconductor laser device lases in a multiple transverse mode and includes a stacked structure where a first conductivity-side semiconductor layer, an active layer, and a second conductivity-side semiconductor layer are stacked above a substrate. The second conductivity-side semiconductor layer includes a current block layer having an opening that delimits a current injection region. Side faces as a pair are formed in portions of the stacked structure that range from part of the first conductivity-side semiconductor layer to the second conductivity-side semiconductor layer. The active layer has a second width greater than a first width of the opening. The side faces in at least part of the first conductivity-side semiconductor layer are inclined to the substrate. A maximum intensity position in a light distribution of light guided in the stacked structure, in a direction of the normal to the substrate, is within the first conductivity-side semiconductor layer.