Surface-Emitting Laser Diffusion Confinement for High-Order Mode Suppression
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Solution Overview
Problem
Surface emitting lasers with oxide confinement layers face issues of high-order mode occurrence and defect growth due to current concentration, which hinders higher-power output and reliability.
Innovation Solution
A method of manufacturing surface emitting lasers involving a semiconductor stacked structure with a first and second DBR layer of different electrical conduction types, where an annular diffusion region of a specific electrical conduction type is formed at the outer edge of a mesa section using impurity diffusion, avoiding high refractive index differences and current concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide confinement is used to form the current confinement layer, then current confinement is achieved, but high-order mode occurs due to large refractive index difference
Solution Approach 1:
The patent changes the confinement mechanism from oxide-based refractive index confinement to impurity diffusion-based electrical conduction type confinement. By forming a diffusion region with a different electrical conduction type (e.g., p-type in n-type DBR layer) instead of using oxide layers, the patent eliminates the large refractive index difference that causes high-order modes while maintaining effective current confinement through electrical properties.
2Object-generated harmful factors
If confinement diameter is decreased to suppress high-order mode, then high-order mode is suppressed, but higher-power output is hindered
Solution Approach 1:
The patent changes the confinement parameter from optical refractive index to electrical conduction type, allowing the confinement diameter to be increased for higher power output without triggering high-order modes. The diffusion region's electrical properties provide effective current confinement regardless of the larger diameter, enabling higher power operation.
3Object-generated harmful factors
If impurity diffusion is used instead of oxide confinement, then high refractive index difference is avoided, but manufacturing process complexity increases
Solution Approach 1:
The patent merges the confinement function with the existing DBR layer structure by forming the diffusion region within the DBR layer during the same manufacturing process. This integration eliminates the need for separate oxide confinement layer formation and reduces overall process complexity despite introducing impurity diffusion steps.
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 suppresses high-order mode occurrence and defect growth, enabling higher-power output while increasing reliability by controlling current confinement and preventing electrical short circuits.
Implementation Method 1
forming an annular diffusion region of the first electrical conduction type at an outer edge of the mesa section by impurity diffusion from a side surface of the mesa section
Implementation Method 2
a first DBR (distributed Bragg reflector) layer of a first electrical conduction type, and a second DBR layer of a second electrical conduction type
Data Source
AI summary
A method of manufacturing a surface emitting laser according to an embodiment of the present disclosure includes the following two steps:(1) a step of forming a semiconductor stacked structure on a substrate, the semiconductor stacked structure including an active layer, a first DBR layer of a first electrical conduction type, and a second DBR layer of a second electrical conduction type, the first DBR layer and the second DBR layer sandwiching the active layer, the second electrical conduction type being different from the first electrical conduction type; and(2) a step of forming a mesa section at a portion on the second DBR layer side in the semiconductor stacked structure and then forming an annular diffusion region of the first electrical conduction type at an outer edge of the mesa section by impurity diffusion from a side surface of the mesa section, the mesa section including the second DBR layer, the mesa section not including the active layer.