Optical Semiconductor Element Tapered Waveguide Beam Quality
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Solution Overview
Problem
Current semiconductor optical amplifiers in the 405 nm band have low beam quality and limited output power, hindering their application in advanced technologies such as next-generation Blu-ray volumetric optical disks and medical fields.
Innovation Solution
An optical semiconductor element with a stacked structure of compound semiconductor layers, featuring a fundamental mode waveguide region, a free propagation region, and a tapered light emitting region, where the axis of the light emitting region intersects the light emitting end surface at an acute angle, enhancing beam quality and output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the optical waveguide width is increased in a tapered shape to expand maximum output, then output power increases, but beam quality deteriorates
Solution Approach 1:
The optical semiconductor element is divided into three distinct functional regions: a fundamental mode waveguide region for mode control, a free propagation region for beam expansion, and a light emitting region for light generation. This segmentation allows each region to optimize its function independently, achieving both high output power and good beam quality simultaneously
Solution Approach 2:
The patent introduces a longitudinal dimension to the waveguide structure by adding the free propagation region between the waveguide and light emitting region. This dimensional extension allows the beam to expand in width without compromising the transverse mode control established in the fundamental mode waveguide region, thereby resolving the contradiction between output power and beam quality
2Power
If a semiconductor optical amplifier is used to amplify laser light, then output power increases, but beam quality remains low
Solution Approach 1:
The fundamental mode waveguide region is designed to establish single-transverse-mode operation before light enters the amplification section. This preliminary mode control ensures that even as power is amplified in the subsequent regions, the beam quality is preserved from the outset
Solution Approach 2:
Different regions of the optical semiconductor element are assigned different structural qualities: the fundamental mode waveguide region has a narrow width for mode control, while the light emitting region has a tapered wide structure for high power output. This local differentiation allows each region to excel at its specific function without compromising the other
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 improved beam quality and increased optical output while maintaining single transverse mode operation, making it suitable for diverse applications including medical and optical shaping fields.
Implementation Method 1
a fundamental mode waveguide region with a waveguide width W1
Implementation Method 2
a free propagation region with a width larger than W1
Implementation Method 3
a light emitting region having a tapered shape with a width increasing toward the light emitting end surface
Data Source
AI summary
Provided is an optical semiconductor element including: a stacked structure body 20 formed of a first compound semiconductor layer 21, a third compound semiconductor layer (active layer) 23, and a second compound semiconductor layer 22. A fundamental mode waveguide region 40 with a waveguide width W1, a free propagation region 50 with a width larger than W1, and a light emitting region 60 having a tapered shape (flared shape) with a width increasing toward a light emitting end surface 25 are arranged in sequence.