VCSEL Resonator Mirror Structure for Stable Transverse Mode
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Solution Overview
Problem
Existing vertical cavity surface emitting devices, such as surface emitting lasers, face challenges in maintaining a stable light emission pattern, particularly in achieving a stable transverse mode for high-output power and low emission angle.
Innovation Solution
The device incorporates a substrate with a first multilayer film reflecting mirror, a light-emitting structure layer, and a second multilayer film reflecting mirror. The second reflecting mirror is designed with a specific structure including low and high refractive index films alternately stacked, an intermediate film for translucency, and a second multilayer film that partially covers the intermediate film, optimizing the resonator configuration for stable transverse mode emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a resonator is configured to generate light in a desired transverse mode, then the far-field pattern stability is improved, but the device structure complexity increases
Solution Approach 1:
The second multilayer film reflecting mirror is segmented into three distinct functional layers: a first multilayer film with alternating low and high refractive index films for optical reflection, an intermediate film for mechanical support and stress relief, and a second multilayer film for additional optical control. This segmentation allows each layer to be optimized independently for its specific function while collectively achieving stable transverse mode emission.
Solution Approach 2:
The second multilayer film reflecting mirror employs composite material structure combining different dielectric materials with contrasting refractive indices (low refractive index material and high refractive index material). This composite approach enables precise control of optical properties including reflectivity spectrum and transverse mode selection, achieving stable far-field patterns through material property optimization rather than complex geometric arrangements.
2Stability of the object's composition
If the second multilayer film reflecting mirror includes an intermediate film with specific thickness, then the transverse mode stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The intermediate film thickness is specifically designed to be 1/4 of the wavelength of the emitted light within the film material. This parameter optimization creates constructive interference conditions that stabilize the transverse mode while providing a sufficiently thick layer for mechanical support and stress relief, reducing sensitivity to minor thickness variations during manufacturing.
Solution Approach 2:
The intermediate film acts as a mediator layer between the first and second multilayer films. It provides mechanical support and stress relief to the brittle multilayer film structures while maintaining optical transparency. The specific thickness of 1/4 wavelength optimizes both mechanical stability and optical performance, reducing the impact of manufacturing tolerances on overall device performance.
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 enables the surface emitting laser to emit light in a stable transverse mode, achieving high-output power with a low emission angle, thereby improving the device's performance and reliability.
Implementation Method 1
The first multilayer film has low refractive index films made of a low refractive index material and high refractive index films made of a high refractive index material having a refractive index higher than a refractive index of the low refractive index material. The low refractive index films and the high refractive index films are alternately stacked.
Implementation Method 2
The intermediate film has a film thickness based on 1/4 of a wavelength inside the intermediate film of a light emitted from the light-emitting layer
Implementation Method 3
The second multilayer film reflecting mirror constitutes a resonator between the first multilayer film reflecting mirror and the second multilayer film reflecting mirror
Data Source
AI summary
A vertical cavity surface emitting device includes a substrate, a first multilayer film reflecting mirror, a light-emitting structure layer with a light-emitting layer, and a second multilayer film reflecting mirror. The second multilayer film reflecting mirror constitutes a resonator between the first and second multilayer film reflecting mirrors. The second multilayer film reflecting mirror includes a first multilayer film, an intermediate film, and a second multilayer film. The first and second multilayer films have low refractive index films and high refractive index films that are alternately stacked. The intermediate film covers an upper surface of the first multilayer film and film has a translucency to a light emitted from the light-emitting layer. The second multilayer film partially covers an upper surface of the intermediate film. The intermediate film has a film thickness based on ½ of a wavelength inside the intermediate film of light emitted from the light-emitting layer.