Semiconductor Laser Diode Current Blocking Layer Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor laser diodes face challenges in maintaining multi-longitudinal mode oscillation and temperature stability across a wide temperature range due to increased current density and heat generation at high temperatures, which affects their performance in on-vehicle applications.
Innovation Solution
A semiconductor laser diode structure with a specific current blocking layer configuration, where the distance from the current blocking layer to the active layer allows current spread beyond the ridge stripe width, stabilizing multi-longitudinal mode oscillation and suppressing heat generation by controlling current density, using a ridge stripe structure with a defined thickness range and material composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the current blocking layer is positioned close to the active layer to confine current, then current density increases and multi-longitudinal mode oscillation is achieved, but heat generation increases and temperature stability deteriorates
Solution Approach 1:
The patent introduces a vertical distance dimension between the current blocking layer and active layer, transforming the current confinement mechanism from purely lateral (2D) to include vertical control (3D). By adjusting the vertical separation distance, the patent achieves current spread beyond the ridge stripe while maintaining confinement, thereby reducing current density and heat generation without sacrificing oscillation stability.
Solution Approach 2:
The patent changes the physical parameter of the distance between the current blocking layer and active layer to optimize performance. By setting this distance to allow current spread beyond the ridge stripe width, the patent simultaneously achieves multi-longitudinal mode oscillation stability and reduced heat generation, resolving the contradiction between these two requirements.
2Object-affected harmful factors
If fast modulation is applied to suppress noise from returned light, then noise reduction is achieved, but device complexity increases due to additional high-frequency superposed modules
Solution Approach 1:
The patent makes the semiconductor laser diode itself perform the noise suppression function through its inherent multi-longitudinal mode oscillation characteristics and self sustained pulsation. The laser structure automatically suppresses noise from returned light without requiring external fast modulation circuits or additional components, thereby achieving noise reduction while maintaining simple device architecture.
3Object-affected harmful factors
If multi-longitudinal mode is employed to suppress noise, then noise reduction is achieved, but gain guide structure increases threshold current and operation power
Solution Approach 1:
The patent optimizes the distance parameter between the current blocking layer and active layer to achieve multi-longitudinal mode oscillation with lower threshold current. By allowing current spread beyond the ridge stripe through vertical separation, the patent reduces operation power while maintaining noise suppression capabilities, unlike conventional gain guide structures that require higher power.
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 enables stable multi-longitudinal mode oscillation and fundamental lateral mode operation across a wide temperature range, reducing heat generation and maintaining high optical output efficiency, suitable for on-vehicle applications.
Implementation Method 1
a distance from a lower face of the current blocking layer to an upper face of the active layer is within a given range, and the current spreads beyond a width of the ridge stripe after passing the ridge stripe and before reaching the active layer
Implementation Method 2
the temperature characteristic can be improved by suppressing heat generation of the diode through reduction of differential resistance owing to a large ridge width
Implementation Method 3
a light emitting portion includes a first cladding layer; an active layer formed on the first cladding layer; a second cladding layer formed on the active layer
Data Source
AI summary
A semiconductor laser diode includes, on a substrate, a first cladding layer; an active layer formed on the first cladding layer; a second cladding layer formed on the active layer and having a ridge stripe for injecting a current into the active layer; and a light emitting portion formed on both sides of the ridge stripe and having a current blocking layer for confining the current in the ridge stripe. A distance from a lower face of the current blocking layer to an upper face of the active layer is within a given range. Also, the current spreads beyond a width of the ridge stripe after passing the ridge stripe and before reaching the active layer.