Light Emitting Element Wavelength Control via Absorbing Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In surface emitting laser elements with long resonator lengths, it is difficult to accurately control the oscillation wavelength due to the presence of multiple longitudinal modes, leading to unstable laser light emission.
Innovation Solution
A light emitting element with a laminated structure comprising a first and second light reflecting layer and a light emitting structure, where at least two light absorbing material layers are integrated in parallel to the active layer, controlling the distance and thickness of these layers to suppress unwanted longitudinal modes and stabilize the oscillation wavelength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the resonator length is increased to enable multiple longitudinal modes, then the laser can operate at multiple wavelengths, but the oscillation wavelength control becomes inaccurate
Solution Approach 1:
The patent divides the resonator into multiple sections by introducing light absorbing material layers at specific positions. These layers segment the optical path and create different loss conditions for different longitudinal modes, enabling wavelength selection and accurate control even in long resonators that support multiple modes.
Solution Approach 2:
The patent applies local quality by positioning light absorbing material layers at specific locations within the resonator where the optical field distribution differs for various longitudinal modes. This creates localized loss regions that selectively attenuate unwanted modes while preserving the desired oscillation wavelength.
2Adaptability or versatility
If the resonator length is increased, then multiple longitudinal modes can oscillate, but the laser emission becomes unstable
Solution Approach 1:
The resonator is segmented by light absorbing material layers that create distinct loss regions. This segmentation suppresses mode hopping and stabilizes the laser emission by ensuring that only the desired longitudinal mode experiences low loss, while other modes are strongly attenuated by the absorbing layers.
Solution Approach 2:
The light absorbing material layers act as intermediaries that mediate between the multiple longitudinal modes and the desired single-mode operation. These layers selectively absorb unwanted modes while allowing the desired mode to oscillate, thereby stabilizing the laser emission.
3Measurement precision
If light absorbing material layers are added to control oscillation wavelength, then wavelength accuracy improves, but the device structure becomes more complex
Solution Approach 1:
The patent merges the light absorbing material layers with existing resonator components such as distributed Bragg reflectors or active layers. By integrating these functions into a unified laminated structure, the device complexity is minimized while achieving accurate wavelength control.
Solution Approach 2:
The light absorbing material layers serve multiple functions: they provide wavelength selection, suppress unwanted longitudinal modes, and can be integrated with other resonator components. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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 allows for precise control of the oscillation wavelength by suppressing undesired laser light modes, resulting in stable and accurate emission of laser light.
Implementation Method 1
at least two light absorbing material layers are formed in parallel to a virtual plane occupied by the active layer
Data Source
AI summary
A light emitting element includes a laminated structure formed by laminating a first light reflecting layer 41, a light emitting structure 20, and a second light reflecting layer 42. The light emitting structure 20 is formed by laminating, from the first light reflecting layer side, a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22. In the laminated structure 20, at least two light absorbing material layers 51 are formed in parallel to a virtual plane occupied by the active layer 23.