Semiconductor Optical Module Cladding Structure for Heat and Light Coupling
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Solution Overview
Problem
Current semiconductor optical modules face challenges in achieving both efficient heat dissipation and optical confinement due to limitations in thermal conductivity and refractive index differences between cladding and active layers, which hinder the efficient coupling of laser light to optical fibers and increase power consumption.
Innovation Solution
A semiconductor optical module is designed with a structure that includes an active layer embedded in a first cladding layer, a second cladding layer made of high thermal conductivity materials like SiC or C, and a third cladding layer with lower thermal conductivity, along with a spot-size converter and heater units to optimize temperature control and refractive index matching for efficient light coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a compound semiconductor (InP, GaAs) is used as the active layer material to achieve light emission, then light emission efficiency is improved, but thermal conductivity is poor causing temperature increase and property degradation
Solution Approach 1:
The patent divides the cladding layer into multiple layers with different materials and functions: a first cladding layer (InP-based) providing optical confinement, a second cladding layer (SiC) providing high thermal conductivity for heat dissipation, and a third cladding layer (SiO2) providing low refractive index for optical confinement. This segmentation allows each layer to specialize in one function without compromise.
Solution Approach 2:
The patent uses composite material structure combining InP-based semiconductor materials with SiC and SiO2. This composite approach integrates the advantages of different materials: InP for optical activity, SiC for thermal management, and SiO2 for optical confinement, resolving the contradiction between light emission efficiency and heat dissipation.
2Stability of the object's composition
If air or insulating film is used as cladding layer material to achieve wide refractive index difference and close optical confinement, then optical confinement is improved, but thermal conductivity decreases and temperature increases
Solution Approach 1:
The patent segments the cladding function into optical confinement (first and third cladding layers) and heat dissipation (second cladding layer), allowing each to be optimized independently without compromising the other.
Solution Approach 2:
The second cladding layer made of SiC acts as an intermediary between the active layer and the substrate, providing a thermal conduction pathway that mediates heat removal without interfering with the optical confinement function performed by the other cladding layers.
3Temperature
If metal material like gold is used as cladding layer to achieve high thermal conductivity, then heat dissipation is improved, but extinction coefficient is high causing large optical absorption loss
Solution Approach 1:
The patent extracts the heat dissipation function from the optical confinement function by using SiC, which provides high thermal conductivity without the harmful optical absorption properties of metals like gold. This separation eliminates the trade-off between thermal management and optical performance.
4Temperature
If Si is used as substrate material to achieve high thermal conductivity, then heat dissipation is improved, but refractive index is high and distance from active layer must be maintained, degrading optical confinement
Solution Approach 1:
The patent segments the functional roles: Si substrate provides thermal management, while the InP-based first cladding layer and SiO2 third cladding layer provide optical confinement. This segmentation eliminates the need for Si to perform both functions simultaneously.
Solution Approach 2:
The InP-based first cladding layer acts as an intermediary between the Si substrate and the active layer, providing optical confinement while allowing the Si substrate to focus on thermal management without direct optical interaction concerns.
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 improves the properties of semiconductor lasers, enhances the efficiency of coupling laser light to optical fibers, and reduces power consumption by effectively managing heat dissipation and refractive index differences.
Implementation Method 1
the second cladding layer is made of a material lower in refractive index and higher in thermal conductivity than the first cladding layer
Implementation Method 2
the optical waveguide element region includes a spot-size converter on which laser light emitted from the semiconductor laser element region is incident
Implementation Method 3
which is composed of a tapered waveguide so as to convert a spot size of the incident laser light
Data Source
AI summary
A semiconductor optical module includes a semiconductor laser element region having an active layer, a first cladding layer which is formed such that the active layer is embedded therein, a second cladding layer which is formed underneath the active layer and the first cladding layer, and a heater unit which produces a temperature change in a waveguide; an optical waveguide element region including a spot-size converter which converts a spot size of incident laser light, and an optical waveguide core layer which is formed such that the spot-size converter is embedded therein, the first cladding layer contains InP, the second cladding layer is made of a material lower in refractive index and higher in thermal conductivity than the first cladding layer, and a third cladding layer which is made of a material lower in refractive index and lower in thermal conductivity than the second cladding layer is formed underneath the spot-size converter and the heater unit.