Off-Cut Broad Area Semiconductor Laser to Eliminate Kinked Output
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Solution Overview
Problem
High fill-factor broad area semiconductor lasers on conventional substrates suffer from inconsistent and unpredictable power performance due to unwanted lateral and ring lasing modes, leading to kinked light-current curves, which limits their application in requiring consistent power output.
Innovation Solution
The use of an off-cut substrate with a cut angle of at least 6 degrees, combined with an epitaxial structure, where sidewalls are parallel and non-perpendicular to the epitaxial layers, preventing total internal reflection and thus eliminating lateral and ring lasing modes, resulting in a kink-free and more predictable light-current performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high fill-factor broad area semiconductor laser is used, then power output is increased, but lateral and ring lasing modes occur causing kinked light-current curves and unpredictable power performance
Solution Approach 1:
The patent applies asymmetry by using an off-cut substrate with a specific crystal orientation angle (e.g., 45 degrees off the (001) plane) to create asymmetric sidewalls that are non-perpendicular to the epitaxial layers. This asymmetric geometry prevents the formation of lateral and ring lasing modes by eliminating the symmetry required for these unwanted modes, thereby achieving kink-free light-current curves while maintaining high fill-factor and power output
2Ease of manufacture
If conventional substrates are used, then manufacturing is simpler, but unwanted lateral and ring lasing modes are generated
Solution Approach 1:
The patent changes the substrate parameter by using an off-cut substrate with a specific crystal orientation angle instead of a conventional (001) oriented substrate. This parameter change in the substrate's crystallographic orientation fundamentally alters the sidewall geometry and light propagation characteristics, eliminating the harmful lateral and ring lasing modes while maintaining compatibility with standard semiconductor manufacturing processes
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 ensures consistent and efficient power performance even at high fill factors, as indicated by smooth light-current curves, allowing for reliable increased power output with increased current application, suitable for applications needing predictable power delivery.
Implementation Method 1
preventing total internal reflection and thus eliminating lateral and ring lasing modes
Data Source
AI summary
A semiconductor laser may include an off-cut substrate having a cut angle of at least approximately 6 degrees (°). The semiconductor laser may include an epitaxial structure over the off-cut substrate. A first sidewall formed by the off-cut substrate and the epitaxial structure may be parallel to a second sidewall formed by the off-cut substrate and the epitaxial structure. A front facet formed by the off-cut substrate and the epitaxial structure may be parallel to a back facet formed by the off-cut substrate and the epitaxial structure. The cut angle of the off-cut substrate may cause the first sidewall to be non-perpendicular to epitaxial layers of the epitaxial structure. The cut angle of the off-cut substrate may cause the second sidewall to be non-perpendicular to the epitaxial layers of the epitaxial structure.