Semiconductor Laser Active Layer Refractive Index Profile
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor lasers have large far-field vertical and lateral beam divergence angles, which affect their coupling efficiency with optical fibers and light output efficiency.
Innovation Solution
A semiconductor laser apparatus with a special refractive index distribution in the active layer, featuring a light producing portion and a light emitting portion with distinct refractive index regions, reduces the far-field beam divergence angles by incorporating a substrate, cladding layers, waveguide layers, and a capping layer, optimizing the beam divergence characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional semiconductor laser structure is used, then manufacturing is simple and inexpensive, but far-field beam divergence angle is large which reduces coupling efficiency with optical fibers
Solution Approach 1:
The active layer is designed with non-uniform thickness, featuring a center region with greater thickness than peripheral regions. This local variation in thickness creates corresponding variations in optical path length and refractive index, enabling the laser beam to be shaped with reduced divergence angles in specific directions without requiring complete structural redesign
Solution Approach 2:
The patent modifies the physical parameters of the active layer, specifically its thickness distribution and refractive index profile. By changing these parameters spatially across the active layer, the optical characteristics of the emitted beam are altered to achieve smaller far-field divergence angles, thereby improving coupling efficiency with optical fibers
2Adaptability or versatility
If beam divergence angle is reduced for better coupling efficiency, then coupling with optical fiber improves, but light output efficiency may be affected
Solution Approach 1:
The active layer employs localized thickness variations where the center region has greater thickness and peripheral regions have lesser thickness. This creates a spatially differentiated optical structure that shapes the beam profile to reduce divergence while preserving the overall light extraction efficiency, as the thickness modifications are optimized to maintain effective light coupling out of the semiconductor structure
Solution Approach 2:
The patent addresses beam divergence by introducing thickness variation in the vertical dimension of the active layer, which then affects the lateral and angular distribution of emitted light. By controlling the optical path length in one dimension (thickness), the beam characteristics in other dimensions (divergence angle, spatial profile) are improved without necessarily compromising total light output
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 semiconductor laser apparatus achieves improved coupling efficiency with optical fibers while maintaining light output efficiency by reducing far-field beam divergence angles, enhancing its performance in applications like optical communication and material processing.
Implementation Method 1
an active layer with a special refractive index distribution
Implementation Method 2
a first type waveguide layer, an active layer, a second type waveguide layer
Data Source
AI summary
A semiconductor laser apparatus is provided and has a substrate, a first type cladding layer, a first type waveguide layer, an active layer, a second type waveguide layer, a second type cladding layer, and a capping layer disposed in sequence. The active layer has a light producing portion and a light emitting portion. A laser produced by the light producing portion, emits along a direction from the light producing portion toward the light emitting portion. The light emitting portion includes a first inactive region, a light emitting region, and a second inactive region. A refractive index of the light emitting region is lower than a refractive index of the first inactive region, the refractive index of the light emitting region is lower than a refractive index of the second inactive region, and width of a first part of the light emitting region continuously increases along the direction.