Surface-Emitting Laser Dielectric Mode Filter
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Solution Overview
Problem
Existing surface-emitting semiconductor laser elements face challenges in maintaining high output in single transverse mode due to increased electric resistance and shortened service life from narrow groove intervals, and manufacturing methods like crystal growth interruptions lead to property variations and low production yield.
Innovation Solution
A surface-emitting laser element structure with a dielectric mode filter having a lower reflection ratio in the peripheral area compared to the center, formed using a tilted substrate and selective oxidation, which reduces electric resistance and stabilizes transverse mode control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If narrow groove intervals are used to prevent higher-order transverse mode oscillation, then transverse mode control is improved, but electric resistance increases and service life shortens
Solution Approach 1:
The patent applies local quality by creating a mode filter with spatially varying reflection ratios - the peripheral area has lower reflection ratio than the center area. This localized differentiation allows the peripheral region to suppress higher-order modes while the center region maintains optimal optical feedback, preventing the need for uniformly narrow grooves that would increase resistance and reduce service life.
2Manufacturing precision
If crystal growth is interrupted for manufacturing the mode filter, then transverse mode control is improved, but property variations increase and production yield decreases
Solution Approach 1:
The mode filter structure is designed and prepared in advance during the crystal growth process, with the peripheral area and center area having predetermined different reflection ratios. This preliminary configuration eliminates the need for interrupting crystal growth during manufacturing, allowing continuous production while maintaining precise transverse mode control and consistent device properties.
3Manufacturing precision
If the peripheral area has lower reflection ratio than the center area, then higher-order transverse mode oscillation is prevented, but device complexity increases
Solution Approach 1:
The patent implements parameter changes by varying the reflection ratio parameter across different spatial regions of the mode filter. The peripheral area is designed with a lower reflection ratio parameter compared to the center area, enabling effective suppression of higher-order modes. This parameter differentiation is achieved through straightforward structural design rather than complex mechanisms, maintaining manufacturing simplicity while achieving superior mode control.
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 solution achieves stable single-mode output with increased production yield and extended service life, allowing for high-volume production and cost-effective manufacturing while preventing higher-order transverse mode oscillation.
Implementation Method 1
A surface-emitting laser element structure with a dielectric mode filter having a lower reflection ratio in the peripheral area compared to the center, formed using a tilted substrate and selective oxidation
Data Source
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AI summary
A surface-emitting laser element (100A) includes a substrate (101); a plurality of semiconductor layers laminated on the substrate (101), the plural semiconductor layers including a resonator structural body including an active layer (105) and semiconductor multilayer film reflection mirrors (103,107) having the resonator structural body sandwiched therebetween; an electrode (113) provided in such a manner as to surround an emitting region on a surface of the surface-emitting laser element (100A) from which light is emitted; and a dielectric film (115) provided in the emitting region such that a reflection ratio of a peripheral part of the emitting region is different from a reflection ratio of a center part of the emitting region. Edge portions that are near edges of the dielectric film (115) are tilted with respect to the surface.