Surface Emitting Semiconductor Laser Moisture Resistance Design
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Solution Overview
Problem
Surface emitting semiconductor lasers have insufficient moisture resistance and low reliability due to the difficulty in controlling the reflectivity or transmissivity of thick insulating layers used for protection, which affects their performance and longevity.
Innovation Solution
A surface emitting semiconductor laser design featuring a substrate with a post structure, multiple insulating layers, and strategically placed openings to enhance moisture resistance while maintaining control over reflectivity, including a first insulating layer on the side and top surfaces, a second insulating layer covering the electrode, and a high reflection film configuration to prevent exposure to humid air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick insulating layer is used to improve moisture resistance, then reliability is improved, but control over reflectivity or transmissivity becomes difficult
Solution Approach 1:
The insulating layer is divided into multiple segments: a first insulating layer (thick, for moisture protection) and a second insulating layer (thin, for optical control). This segmentation allows each layer to be optimized for its specific function - the first layer provides sufficient thickness for moisture resistance while the second layer enables precise control over reflectivity and transmissivity without being constrained by the thickness of the first layer.
Solution Approach 2:
Different regions of the insulating structure are assigned different thicknesses and properties. The first insulating layer has large thickness specifically in regions requiring moisture protection, while the second insulating layer provides localized optical control. This local differentiation allows simultaneous achievement of moisture resistance and optical property control.
2Object-affected harmful factors
If the insulating layer thickness is increased to prevent exposure to humid air, then moisture resistance is improved, but the ability to control optical characteristics deteriorates
Solution Approach 1:
The protective insulating structure is segmented into two functional layers: the first insulating layer provides thick protection against humid air penetration, while the second insulating layer is designed with controlled thickness to enable precise optical characteristics. This segmentation decouples the conflicting requirements of thick protection and precise optical control.
Solution Approach 2:
The multi-layer insulating structure serves multiple functions simultaneously: the first layer provides moisture barrier function, while the second layer provides optical control function. Together, they create a unified structure that achieves both protection from humid air and control over optical characteristics.
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 design achieves high moisture resistance and reliability, with no significant degradation in electrical or light-emitting characteristics after a 2000-hour humidity test at 85°C and 85% relative humidity, ensuring stable performance.
Implementation Method 1
a post disposed on the first area of the substrate, the post including a stacked semiconductor layer including an active layer and a distributed Bragg reflector
Data Source
AI summary
A surface emitting semiconductor laser includes a post disposed on a substrate, the post including an active layer and a distributed Bragg reflector; a first insulating layer disposed on side and top surfaces of the post and on the substrate, the first insulating layer having an opening on the top surface of the post; an electrode disposed in the opening of the first insulating layer; an electric conductor including a pad electrode on the first insulating layer, the electric conductor extending on the first insulating layer to the electrode; and a second insulating layer disposed on the first insulating layer, the electrode, and the electric conductor so as to cover the electrode in the opening of the first insulating layer, the second insulating layer having an opening on the pad electrode, the opening of the second insulating layer having an edge on a top surface of the pad electrode.