Photonic Crystal Laser Diode Contact Layout for Gaussian Beams
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Solution Overview
Problem
Existing laser diode components face challenges in achieving high output power while maintaining a symmetric Gaussian beam profile, particularly when enlarging the emission aperture, as current crowding near the contact structure often leads to a deterioration of the beam profile into a donut shape, which is problematic for high power lasers needing Gaussian beam coupling into fibers.
Innovation Solution
The laser diode component incorporates a photonic crystal structure with regularly arranged structured portions forming a two-dimensional lattice, and contact portions that penetrate the active zone, allowing for homogeneous current injection and maintaining a symmetric beam profile even with enlarged apertures, using transparent and reflective conductive materials to minimize radiation losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the emission aperture is enlarged to increase output power, then the power output is improved, but the beam profile deteriorates from Gaussian to donut shape
Solution Approach 1:
The contact structure is divided into multiple discrete contact portions arranged in a periodic pattern rather than a single continuous contact. This segmentation prevents current crowding at the contact edges while distributing current injection uniformly across the enlarged aperture, maintaining Gaussian beam profile even at high power levels
Solution Approach 2:
The contact portions are strategically positioned in specific regions (such as in recesses or at specific depths) to create localized current injection zones. This local quality control ensures uniform current distribution across the aperture while allowing the overall aperture to be enlarged for high power output
2Ease of operation
If the contact structure is made ring-shaped to enable current injection, then current injection is achieved, but current crowding occurs near the contact structure
Solution Approach 1:
The continuous ring-shaped contact is segmented into multiple discrete contact portions arranged periodically. This segmentation eliminates the current crowding effect that occurs at the edges of continuous ring contacts while maintaining effective current injection into the active zone
Solution Approach 2:
The contact structure transitions from a two-dimensional ring shape to a three-dimensional periodic arrangement of discrete portions at specific depths or positions. This dimensional change allows current to be injected more uniformly across the aperture by distributing contact points in space
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 enables high-performance laser diode components with power outputs ranging from 1 W to over 10 W, operating in pulsed or continuous wave modes, and emitting a symmetric Gaussian beam profile with reduced radiation losses and improved beam quality.
Implementation Method 1
PCSELs are devices that use photonic crystals inter alia to obtain vertical laser emission. The photonic crystal structure comprises a plurality of structured portions that cause a periodic change of the refractive index in which a photonic band structure is formed
Implementation Method 2
a semiconductor layer stack including an active zone for emitting laser radiation. one contact comprising a plurality of contact portions arranged in recesses of the semiconductor layer stack and penetrating the active zone
Data Source
Figure 1
Figure 2
AI summary
A laser diode component (1) is described comprising: - a semiconductor layer stack (2) comprising an active zone (4) for emitting laser radiation, - a photonic crystal structure (8) comprising a plurality of structured portions (10), contacts (12) for electrically contacting the laser diode component (1), one contact (13, 20) comprising a plurality of contact portions (21) arranged in recesses (24) of the semiconductor layer stack (2), wherein the contact portions (21) penetrate the active zone (4).