Surface Emitting Laser Oxide Layer Thickness Optimization
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Solution Overview
Problem
Surface emitting laser elements with oxide confinement structures exhibit negative droop characteristics, leading to unstable light output and potential image quality issues due to self-heating effects, which affect the service life and image clarity in electrophotographic applications.
Innovation Solution
A surface emitting laser element with a resonator structural body and semiconductor distributed Bragg reflectors that include an oxide confinement structure to confine injection current and lateral mode oscillation, where the thickness of the selectively oxidized layer is at least 25 nm, ensuring the oscillation threshold current is minimized at 25 °C or less, thereby preventing negative droop characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an oxide confinement structure is used to increase current injection efficiency, then light output stability deteriorates due to negative droop characteristics caused by self-heating effects
Solution Approach 1:
The patent changes the thickness parameter of the oxide confinement layer to at least 25 nm, which modifies the thermal and optical properties of the structure. This parameter change reduces self-heating effects and prevents negative droop characteristics, thereby maintaining light output stability while preserving current injection efficiency.
Solution Approach 2:
The patent employs a composite structure combining semiconductor materials with an oxide confinement layer. This composite design allows the oxide layer to provide both current confinement and thermal management functions, resolving the contradiction between efficiency and stability by integrating multiple functions into a single structured system.
2Reliability
If the thickness of the selectively oxidized layer is increased to improve current confinement, then service life may be shortened due to excessive self-heating
Solution Approach 1:
The patent specifies a minimum thickness of 25 nm for the selectively oxidized layer, which optimizes the balance between current confinement and thermal management. This parameter setting ensures sufficient confinement while preventing excessive self-heating that would reduce service life.
Solution Approach 2:
The patent establishes a feedback mechanism where the thickness of the oxide layer is controlled to prevent negative droop characteristics. By monitoring and controlling the thickness parameter, the system maintains optimal performance and extends service life through preventive thermal management.
3Ease of manufacture
If conventional oxide confinement structures are used, then image quality deteriorates due to unstable light output during scanning
Solution Approach 1:
The patent modifies the oxide layer thickness parameter to at least 25 nm, which stabilizes light output and eliminates negative droop characteristics. This parameter change improves image quality by ensuring consistent light emission during scanning while maintaining ease of manufacture through a straightforward structural modification.
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 negative droop characteristics across various pulse periods without shortening the service life of the laser element, maintaining stable light output and image quality by optimizing light confinement and thermal management.
Implementation Method 1
a confinement structure which can confine an injection current and a lateral mode of oscillation light at the same time by surrounding a current passing through region with an oxide containing at least an oxide formed by oxidizing a part of a layer to be selectively oxidized containing aluminum
Implementation Method 2
first and second semiconductor distributed Bragg reflectors which sandwich the resonator structural body
Implementation Method 3
an active layer, and first and second semiconductor distributed Bragg reflectors which sandwich the resonator structural body
Data Source
Figure 1
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AI summary
A surface emitting laser element is disclosed. The surface emitting laser element includes a resonator structural body including an active layer, first and second semiconductor distributed Bragg reflectors which sandwich the resonator structural body, and a confinement structure which can confine an injection current and a lateral mode of oscillation light at the same time by being formed with selective oxidation of a layer to be selectively oxidized containing aluminum in the first semiconductor distributed Bragg reflector. A thickness of the layer to be selectively oxidized is 28 nm, and a temperature when an oscillation threshold current becomes a minimum value is approximately 17 °C.