Composite Cavity Semiconductor Laser for Thermal and Power Efficiency
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Solution Overview
Problem
Current vertical-cavity surface-emitting lasers (VCSELs) face limitations in thermal management and optical power efficiency due to the materials used in their construction, which can lead to reduced performance at high optical power levels and increased risk of optical damage.
Innovation Solution
A composite cavity laser (CCL) is developed, integrating an upper narrow bandgap semiconductor structure with a lower wide bandgap semiconductor structure, utilizing a coupler to guide lasing light and incorporating a distributed Bragg reflector or distributed feedback structure for efficient lasing, while the wide bandgap structure provides enhanced thermal management and low-loss waveguiding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional VCSEL materials are used, then the device structure is simple, but thermal management performance deteriorates and optical power efficiency decreases
Solution Approach 1:
The patent applies composite materials by integrating two different semiconductor materials with distinct bandgap energies into a single laser device. The first material (e.g., GaAs) provides efficient lasing action, while the second material (e.g., AlGaAs or InP) provides superior thermal management and low-loss waveguiding, resolving the contradiction between simple structure and thermal performance
Solution Approach 2:
The laser device is segmented into distinct functional regions using different materials: the narrow bandgap material forms the active region for lasing, while the wide bandgap material forms the waveguide and thermal management layer. This segmentation allows each material to optimize its specific function, improving overall thermal management without compromising structural integrity
2Reliability
If traditional VCSEL materials are used, then manufacturing is simpler, but optical power efficiency and reliability deteriorate at high power levels
Solution Approach 1:
The composite material structure enhances reliability by using wide bandgap materials with higher damage thresholds in the waveguide and thermal management regions, while maintaining narrow bandgap materials for efficient lasing. This material composition resolves the contradiction between manufacturing simplicity and optical damage resistance
Solution Approach 2:
Different regions of the laser device are assigned different material qualities optimized for their specific functions: the active region uses narrow bandgap material for high gain, while the waveguide and thermal management regions use wide bandgap materials for high damage threshold and low loss. This local optimization improves reliability without requiring complete structural redesign
3Use of energy by moving object
If narrow bandgap semiconductor is used for the cavity, then lasing efficiency is improved, but thermal removal capability deteriorates
Solution Approach 1:
The device is segmented into an active region using narrow bandgap material for efficient lasing and a separate thermal management region using wide bandgap material for superior heat conduction. This segmentation allows the narrow bandgap material to maximize lasing efficiency while the wide bandgap material handles thermal removal, resolving the contradiction between energy efficiency and thermal management
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 CCL achieves improved thermal removal of heat, increased optical power efficiency, and reduced optical damage risk, enabling higher performance and reliability at high power levels with enhanced coupling to external optical fibers.
Implementation Method 1
Each mirror stack includes a number of epitaxial layers of alternating refractive index values (e.g., alternating between 'high' and 'low' refractive index values). As light passes from a layer of one index of refraction to another, a portion of the light is reflected, creating a diffractive Bragg reflector (DBR) structure. By using a sufficient number of alternating layers, a high percentage of light is reflected and creates a standing wave pattern across the cavity.
Implementation Method 2
utilizing a coupler to guide lasing light and incorporating a distributed Bragg reflector or distributed feedback structure for efficient lasing
Data Source
AI summary
A laser may include a lower semiconductor structure and an upper semiconductor structure. The lower semiconductor structure may include a lower waveguide along a top side of the lower semiconductor structure. The upper semiconductor structure may include an upper waveguide along a bottom side of the upper semiconductor structure. The upper semiconductor structure may be positioned over the top side of the lower semiconductor structure such that a first portion of the upper waveguide vertically overlaps a second portion of the lower waveguide. A coupler between the upper waveguide and the lower waveguide may couple optical energy of the upper waveguide to the lower waveguide. The lower waveguide may comprise semiconductor material having a wider bandgap than semiconductor material of the upper waveguide.