DFB Laser and Semiconductor Optical Amplifier for Green Light Generation
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Solution Overview
Problem
Current semiconductor laser systems struggle to efficiently emit green light due to limitations in modulating laser light intensity and wavelength, particularly at high speeds, which hampers applications like laser projection.
Innovation Solution
A laser system comprising a DFB laser, a semiconductor optical amplifier, and a harmonic generation element that converts the modulated laser light into visible green light, allowing for intensity modulation without changing the wavelength, thereby enhancing efficiency and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the wavelength of the laser light emitted by the semiconductor laser is fixed to improve conversion efficiency by the non-linear optical element, then the conversion efficiency is improved, but the intensity of the laser light cannot be modulated
Solution Approach 1:
The invention divides the laser system into two separate functional modules: a DFB laser module that generates laser light at a fixed wavelength optimized for harmonic conversion, and a semiconductor optical amplifier module that performs intensity modulation. This segmentation allows each module to specialize in its respective function, maintaining high conversion efficiency while enabling intensity modulation capability.
Solution Approach 2:
The invention introduces a semiconductor optical amplifier as an intermediary component between the DFB laser and the non-linear optical element. This intermediary allows the laser wavelength to remain fixed for optimal conversion efficiency while the amplifier modulates the intensity of the laser light before it reaches the non-linear optical element, thus resolving the contradiction between fixed wavelength and intensity modulation.
2Device complexity
If a semiconductor laser that emits green light is realized to simplify the system, then the system structure is simplified, but high-speed modulation capability and conversion efficiency are compromised
Solution Approach 1:
Instead of directly emitting green light from the semiconductor laser, the invention uses a DFB laser to generate infrared light that is then converted to green light through harmonic generation in a non-linear optical element. This indirect approach (copying the green light generation process through frequency doubling) preserves the advantages of both DFB lasers (stable wavelength, high power) and green light emission (visibility, application suitability).
Solution Approach 2:
The invention replaces the mechanical/electrical modulation approach with optical modulation using a semiconductor optical amplifier. The amplifier uses optical gain modulation to achieve high-speed intensity modulation of the laser light, enabling modulation speeds up to 100 MHz while maintaining system simplicity and efficiency.
3Loss of energy
If the tolerable wavelength range is narrowed to improve conversion efficiency, then the conversion efficiency is improved, but the device becomes less adaptable to wavelength variations
Solution Approach 1:
The invention applies local quality optimization by using a DFB laser that emits at a specific wavelength precisely matched to the peak conversion efficiency point of the non-linear optical element. The DFB laser's inherent wavelength stability and narrow linewidth ensure that the laser operates at the optimal wavelength for harmonic conversion, maximizing conversion efficiency while the semiconductor optical amplifier provides the necessary adaptability for intensity control.
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 system achieves efficient modulation of laser light intensity and reduces power consumption while maintaining high-speed modulation capabilities, enabling the emission of green light for applications such as laser projection.
Implementation Method 1
a DFB laser having a quantum dot active layer from which a laser light is emitted
Implementation Method 2
a harmonic generation element that converts the laser light to a visible light that is a harmonic of the laser light
Data Source
AI summary
The present invention is a laser system including a DFB laser 10 emitting a laser light 50, a semiconductor optical amplifier 20 that modulates an intensity of the laser light, and a harmonic generation element 30 that converts the laser light modulated to a visible light 54 that is a harmonic of the laser light. According to the present invention, it is possible to employ the highly efficient harmonic generation element capable of modulating the intensity of the laser light and to reduce power consumption.