MQW Optical Structure With Local Heating for Bandgap Separation
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Solution Overview
Problem
Existing optical devices with integrated light sources and modulators face challenges in manufacturing due to the difficulty in varying the bandgap wavelength of semiconductor materials between the light source and modulator areas, leading to inefficient heat transmission and high production costs.
Innovation Solution
The optical device incorporates a multiple quantum well (MQW) active layer across both the light source and modulator areas, with a heater applied to the light source area to reduce its energy bandgap. The second cladding layer has a wider upper side to facilitate electrode formation and concentrate heat generated by the heater in the active area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If selective area growth (SAG) technique is used to vary bandgap wavelength between DFB-LD area and EA modulator area, then the energy bandgap difference is achieved, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent applies local quality by creating a local temperature difference within the semiconductor structure. A heater is introduced in the DFB-LD area to locally increase temperature, which locally reduces the energy bandgap in that specific region while keeping the EA modulator area at its original bandgap, thus achieving the required bandgap difference without complex manufacturing processes
Solution Approach 2:
The patent changes the temperature parameter of the DFB-LD area using a heater. By increasing the temperature in the DFB-LD region, the energy bandgap is reduced due to thermal effects, allowing the DFB-LD area to have a smaller energy bandgap than the EA modulator area without requiring different semiconductor materials or complex growth techniques
2Temperature
If heat is generated in the light source area, then the energy bandgap can be reduced, but the heat may disperse and reduce thermal energy efficiency
Solution Approach 1:
The patent uses an asymmetric cladding layer structure where the cladding layer thickness is designed to be different in the DFB-LD area compared to the EA modulator area. This asymmetric structure acts as a thermal guide, concentrating and directing heat toward the DFB-LD active region while preventing heat dispersion, thereby improving thermal energy efficiency
Solution Approach 2:
The cladding layer serves as a thermal intermediary that guides and concentrates heat flow. By designing the cladding layer with specific thickness variations, it mediates the heat transmission process, ensuring that heat generated in the DFB-LD area remains concentrated in the active region rather than dispersing, thus improving thermal efficiency
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 solution allows for the efficient reduction of the light source's energy bandgap, enabling normal operation of the modulator while simplifying manufacturing by allowing easy electrode formation and improving thermal energy efficiency through concentrated heat transmission.
Implementation Method 1
a heater controlling an energy bandgap of a light source by applying heat to the MQW active layer corresponding to the light source area
Data Source
AI summary
The present invention provides an optical device comprising: a first cladding layer formed on a substrate; a multiple quantum well (MQW) active layer formed on the first cladding layer all over a light source area and a modulator area; a second cladding layer formed on the MQW active layer; and a heater, which applies heat to the MQW active layer corresponding to the light source area, and thus controls an energy bandgap of a light source.