Multiple Distributed Feedback Laser Devices for Terahertz Generation
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Solution Overview
Problem
Existing semiconductor-based optical devices, particularly distributed feedback laser diodes used for generating terahertz waves through the photomixing method, require complex structures and auxiliary devices to stabilize the frequency of laser beams, leading to increased manufacturing costs and complexity.
Innovation Solution
A multiple distributed feedback laser device with independently controlled micro heaters for diffraction gratings, allowing for precise adjustment of refractive indices and wavelengths, integrated with a substrate and cladding layers to stabilize and oscillate multiple light sources efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary devices are used to stabilize the frequency of laser beams in the photomixing method, then the frequency stability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The distributed feedback laser diode structure uses internal diffraction gratings formed directly in the waveguide layers to provide frequency selection and stabilization. The feedback mechanism is self-contained within the laser cavity, eliminating the need for external auxiliary devices. The grating structures provide automatic frequency control through the feedback loop inherent in the distributed feedback mechanism.
Solution Approach 2:
The diffraction grating structures are integrated directly into the laser diode waveguide layers, merging the frequency selection function with the light generation function. The multiple distributed feedback regions are combined in a single integrated device structure, allowing multiple wavelengths to be generated simultaneously without requiring separate auxiliary stabilization devices for each wavelength.
2Productivity
If multiple distributed feedback regions are integrated in a single device, then the generation efficiency of terahertz waves is improved, but the manufacturing precision requirement increases
Solution Approach 1:
The device is divided into multiple distributed feedback regions, each with its own diffraction grating structure optimized for a specific wavelength. This segmentation allows each region to be designed and fabricated with precise control over its grating parameters, while the overall device achieves high generation efficiency through the coordinated operation of multiple regions.
Solution Approach 2:
Different diffraction grating structures with varying parameters (period, depth, duty cycle) are used in different distributed feedback regions to optimize for different wavelengths. By changing the grating parameters according to the specific wavelength requirements of each region, the device achieves high precision frequency selection while maintaining manufacturability through standard semiconductor fabrication processes.
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 device achieves superior reliability and high integration, improving the generation efficiency of terahertz waves by stabilizing the oscillation of multiple light sources with coherent characteristics, reducing complexity and manufacturing costs.
Implementation Method 1
a first micro heater supplying heat to the first diffraction grating; and a second micro heater supplying heat to the second diffraction grating
Implementation Method 2
a refractive index of the first diffraction grating may be changed by the heat supplied from the first micro heater, and a refractive index of the second diffraction grating may be changed by the heat supplied from the second micro heater
Implementation Method 3
only a lightwave having a specific wavelength corresponding to a bragg wavelength due to a periodic change of a refractive index may be reflected
Implementation Method 4
The functional laser devices may filter a wavelength using a diffraction grating
Implementation Method 5
a first laser current may be supplied to the active layer in the first distributed feedback region to oscillate a first light source having a first wavelength
Data Source
AI summary
Provided is a multiple distributed feedback laser device. The laser device includes an active layer, a first diffraction grating, and a second diffraction grating. The substrate includes a first distributed feedback region, a modulation region, and a second distributed feedback region. The first diffraction grating is coupled to the active layer in the first distributed feedback region. The second diffraction grating is coupled to the active layer in the second distributed feedback region. In addition, the laser device includes a first micro heater and a second micro heater. The first micro heater supplies heat to the first diffraction grating. The second micro heater supplies heat to the second diffraction grating. The first micro heater and the second micro heater are controlled independently from each other.