Convex-Portion Laser Element Prevents Ray Scattering
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Solution Overview
Problem
Conventional surface emitting laser devices suffer from optical intensity loss and disturbance in the Far Field Pattern due to scattered marginal rays caused by the concave shape of the exit aperture and the side-wall portion of the DBR mirror, leading to reduced laser performance.
Innovation Solution
A surface emitting laser device with a convex-portion forming layer between the current-confinement aperture and the multilayer mirror, forming a convex portion on each boundary between layers, ensuring the plane surface area is equal to or larger than the laser spot size, thereby preventing marginal ray scattering and maintaining optical intensity within a predetermined diffraction angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a concave-shaped exit aperture is formed on the spatial filter layer to improve laser light transmission, then the laser light can pass through the DBR mirror more effectively, but the marginal rays are scattered by the side-wall portion of the concave structure causing optical intensity loss and disturbance in the Far Field Pattern
Solution Approach 1:
The patent inverts the conventional concave-shaped exit aperture into a convex-shaped exit aperture. This inversion changes the geometry from concave to convex, eliminating the side-wall scattering problem while maintaining the improved light transmission characteristics. The convex shape prevents marginal rays from being scattered by side walls, thus resolving the Far Field Pattern disturbance issue.
Solution Approach 2:
The patent employs a convex curved surface for the exit aperture instead of a flat or concave structure. The convex curvature is specifically designed to match the spot size of the laser light, ensuring that the curved surface is equal to or larger than the spot size. This curvature design optimizes light transmission while preventing marginal ray scattering.
2Illumination intensity
If the convex portion area is increased to prevent marginal ray scattering, then optical intensity is maintained, but the device structure becomes more complex
Solution Approach 1:
The patent applies local quality by making the convex portion's area specifically equal to or larger than the laser light spot size at the critical location where marginal rays exit. This localized design ensures optical intensity maintenance only where needed, rather than increasing the entire device structure, thus avoiding unnecessary complexity.
Solution Approach 2:
The patent optimizes the convex portion area as a specific parameter - making it equal to or larger than the spot size of the laser light. This parameter change ensures sufficient area to prevent marginal ray scattering while avoiding excessive size increases that would complicate the device structure.
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 effectively prevents optical intensity loss and disturbance in the Far Field Pattern, enhancing laser performance by ensuring the marginal rays are not scattered, thus maintaining high optical intensity and clear emission patterns.
Implementation Method 1
a light generated by an active layer 21 based on an injected current is resonated between a lower DBR mirror 22 and an upper DBR mirror 23
Implementation Method 2
a distributed Bragg reflector (DBR) mirror, which is a multilayer mirror, is used in a resonator
Implementation Method 3
a predetermined diffraction angle of the laser light due to the current-confinement aperture
Data Source
AI summary
A convex-portion forming layer is formed between a current-confinement aperture and a multilayer mirror, and forms a convex portion on each boundary between layers forming the multilayer mirror. The convex portion includes a plane equal to or larger than a spot size of the laser light, where the spot size is decided by a diameter of the current-confinement aperture, a predetermined diffraction angle of the laser light due to the current-confinement aperture, and a distance from the current-confinement aperture.