Semiconductor Laser with Light Absorption Layer for High-Temperature Stability
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Solution Overview
Problem
Conventional semiconductor lasers experience unstable oscillation and high operating current at high temperatures, particularly in self-pulsation mode, which limits their effectiveness in optical information processing devices.
Innovation Solution
A semiconductor laser design featuring a substrate with a first conduction-type cladding layer, an active layer, a second conduction-type cladding layer with a stripe-shaped ridge structure, a current block layer composed of Al-containing compounds, and a light absorption layer, where the current block layer has a lower Al composition ratio than the cladding layer, allowing for independent current and light confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional self-pulsation laser design is used, then miniaturization and low cost are achieved, but stable oscillation at high temperature cannot be guaranteed
Solution Approach 1:
The patent divides the cladding layer into two independent functional layers: a first conduction-type cladding layer for current confinement and a second conduction-type cladding layer for light confinement. This segmentation allows each layer to be optimized independently, enabling stable high-temperature operation while maintaining device simplicity
Solution Approach 2:
The patent applies different material compositions and properties to different regions: the first cladding layer uses a composition optimized for current blocking, while the second cladding layer uses a composition optimized for light guidance. This local differentiation of properties enables simultaneous optimization of both current and light confinement functions
2Object-affected harmful factors
If high-frequency superposing circuit is added to reduce noise, then noise reduction is achieved, but device miniaturization is hindered
Solution Approach 1:
The patent makes the laser diode itself generate high-frequency self-pulsation through its internal structure (the independent current and light confinement layers), eliminating the need for external high-frequency superposing circuits. The device serves its own noise reduction function internally
Solution Approach 2:
The patent extracts the high-frequency generation function from an external circuit and integrates it into the laser diode's internal structure through the specific layer configuration, removing the need for separate noise reduction components
3Temperature
If operating current is increased to maintain oscillation at high temperature, then high-temperature operation is achieved, but operating efficiency decreases
Solution Approach 1:
The patent changes the structural parameters of the laser diode by introducing independent current and light confinement layers with specific material compositions. This structural parameter change enables low-threshold operation at high temperatures without increasing operating current
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 design enables stable oscillation and low operating current even at high temperatures, suitable for miniaturized optical information processing devices without the need for additional high-frequency circuits.
Implementation Method 1
a light absorption layer provided on the current block layer and absorbs light at a laser oscillation wavelength
Data Source
AI summary
Provided is a semiconductor laser which has a low operating current and stably oscillates even for high-temperature output. The semiconductor laser is provided with a substrate (10); an n-type clad layer (12) arranged on the substrate (10); an active layer (13) arranged on the n-type clad layer (12); a p-type clad layer (14), which is arranged on the active layer (13) and composed of a compound containing Al and has a stripe-shaped ridge structure to be a current channel; a current block layer (16), which is arranged on the surface of the p-clad layer (14) excluding an upper surface of the ridge structure and composed of a compound containing Al and has an Al composition ratio not more than that of the p-type clad layer (14); and a light absorption layer (17), which is arranged on the current block layer (16) and absorbs light at the laser oscillation wavelength.