Asymmetric Double Waveguide Semiconductor Laser for Facet Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Edge emitter semiconductor lasers face catastrophic optical degradation (COD) and gradual degradation due to high power density at the exit window facets, leading to irreversible damage, with existing solutions either reducing power density or using complex etch-regrowth methods that are difficult to process and may shift degradation issues.
Innovation Solution
The use of planar asymmetric, double waveguide, low confinement semiconductor laser structures with modified transversal layered end segments that gradually reduce the upper cladding thickness towards the windows, significantly decreasing the fundamental mode confinement factor and reducing power density at the window facets, while minimizing transfer losses to higher-order modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high power density is used to increase laser output power, then productivity is improved, but catastrophic optical degradation occurs at the exit window facets
Solution Approach 1:
The laser cavity is divided into a main amplifying segment and an end segment. The end segment contains a modified layered structure with asymmetric waveguides that segments the optical path, allowing high power generation in the main segment while protecting the window facet in the end segment from catastrophic degradation.
Solution Approach 2:
The end segment introduces local structural modifications with asymmetric waveguides having different confinement factors. This creates localized regions with different optical properties - the main segment maintains high confinement for efficient amplification, while the end segment has reduced confinement to protect the window facet from high power density.
2Reliability
If complex etch-regrowth methods are used to protect window facets, then reliability is improved, but device complexity increases
Solution Approach 1:
The invention changes the structural parameters of the layered semiconductor system by introducing an end segment with modified layer thicknesses and asymmetric waveguide configurations. This parameter modification provides window facet protection through gradual field distribution changes rather than through complex etch-regrowth processes.
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 substantially decreases the power density at the window facets, reducing catastrophic degradation and slowing down gradual degradation processes, thereby enhancing the operational resilience of semiconductor lasers at high power levels.
Implementation Method 1
The end segments have planar layered optical structures derived from the main structure... Both optical structures have asymmetric index of refraction profiles relative to a planar core waveguide... The thickness of the upper cladding of the optical structures of end segments decreases gradually toward windows
Implementation Method 2
Both optical structures have asymmetric index of refraction profiles relative to a planar core waveguide... The asymmetry in structure determines an asymmetry of the propagating radiation field distribution in a transversal section
Implementation Method 3
edge emitter semiconductor lasers, wherein the amplification by stimulated emission (laser effect) is produced along a device that is millimeters long
Data Source
Figure 1~2C
Figure 3~4
Figure 5~6
AI summary
Semiconductor laser device with mirror protection includes transversally a structure with a double waveguide, consisting of an active waveguide and a separated or adjacent trapping waveguide, and longitudinally a main segment and end segments, the thickness of the upper cladding of the end segments being gradually decreased toward the mirrors. In the main segment, the field distribution is asymmetric, preponderantly located in the lower cladding. In the end segments, the field distribution gradually further shifts toward the lower cladding. Along the end segments, the fundamental mode confinement factor Γ is gradually and substantially reduced. The reduction of the confinement factor Γ protects against degradation the projection of the active region on the exit mirrors, the laser element most sensitive to degradation.