Surface-Emitting Laser Reflectance Control via Contact Layer Thickness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surface-emitting laser devices face limitations in suppressing high-order side mode oscillations without reducing light output in the basic side mode, with previous methods either increasing manufacturing complexity or leading to unstable reflectance differences and reduced luminous efficiency.
Innovation Solution
A surface-emitting laser device with a laminated structure including a lower multilayer film reflecting mirror, a resonator structure, an upper multilayer film reflecting mirror, and a contact layer, where a transparent dielectric layer is used to create a reflectance difference between the central and peripheral regions, with the contact layer's thickness varying between high and low reflectance regions to deviate from odd multiples of the oscillation wavelength's quarter optical thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent dielectric layer is formed on the emitting surface to reduce peripheral reflectance, then high-order side mode oscillations are suppressed, but the reflectance difference becomes unstable and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by making the contact layer thickness non-uniform across the emitting surface. The contact layer is thinner at the center and thicker at the periphery, creating different optical characteristics in different regions. This local variation in thickness produces the desired reflectance difference between central and peripheral regions, suppressing high-order side mode oscillations without requiring complex multi-layer dielectric structures.
Solution Approach 2:
The patent changes the physical parameter of contact layer thickness to control optical reflectance. By varying the contact layer thickness from center to periphery, the patent achieves different reflectance values in different regions. This parameter change approach simplifies manufacturing compared to forming multiple dielectric layers with precise thickness control, while effectively suppressing mode oscillations.
2Reliability
If the contact layer thickness is varied to create reflectance difference, then high-order side mode oscillations are suppressed, but light output in basic side mode may be reduced
Solution Approach 1:
The patent applies local quality by making the contact layer thickness non-uniform across the emitting surface. The contact layer is thinner at the center and thicker at the periphery, creating different optical characteristics in different regions. This local variation in thickness produces the desired reflectance difference between central and peripheral regions, suppressing high-order side mode oscillations without requiring complex multi-layer dielectric structures.
Solution Approach 2:
The patent uses partial action by creating reflectance difference only in the peripheral region while maintaining high reflectance in the central region. The contact layer thickness variation is applied selectively - thinner at center for high reflectance, thicker at periphery for low reflectance. This partial application of thickness variation suppresses mode oscillations while preserving light output in the basic mode.
3Reliability
If multiple dielectric layers are laminated to create reflectance difference, then side mode control is improved, but manufacturing processes increase
Solution Approach 1:
The patent applies local quality by making the contact layer thickness non-uniform across the emitting surface. The contact layer is thinner at the center and thicker at the periphery, creating different optical characteristics in different regions. This local variation in thickness produces the desired reflectance difference between central and peripheral regions, suppressing high-order side mode oscillations without requiring complex multi-layer dielectric structures.
Solution Approach 2:
The patent extracts the essential function of creating reflectance difference from the complex multi-layer dielectric structure and implements it through a simpler single contact layer with variable thickness. By taking out the core requirement (reflectance difference) and implementing it through contact layer thickness variation, the patent eliminates the need for multiple dielectric layer deposition processes while achieving the same side mode control effect.
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 configuration effectively suppresses high-order side mode oscillations while maintaining or enhancing light output in the basic side mode, improving the precision of optical scanning and image forming capabilities.
Implementation Method 1
a transparent dielectric layer is provided in an emitting region surrounded by an electrode and configured to cause a reflectance difference between a central part and a peripheral part in the emitting region
Implementation Method 2
the total optical thickness of the high refractive index layer and the contact layer in the region having the relatively low reflectance is deviated from an odd number multiple of a one quarter oscillation wavelength of laser light
Data Source
AI summary
A surface-emitting laser device includes a transparent dielectric layer provided in an emitting region and configured to cause a reflectance at a peripheral part to be different from a reflectance at a central part in the emitting region. In the surface-emitting laser device, the thickness of a contact layer is different between a region having a relatively high reflectance and a region having a relatively low reflectance in the emitting region. The contact layer is provided on the high refractive index layer of an upper multilayer film reflecting mirror, and the total optical thickness of the high refractive index layer and the contact layer in the region having the relatively low reflectance is deviated from an odd number multiple of a one quarter oscillation wavelength of laser light emitted from the emitting region.