Coupled Ring Resonator Laser for High-Power Single-Mode Lasing
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Solution Overview
Problem
Current semiconductor laser elements, particularly GaN lasers, face challenges in achieving high brightness and high power single-mode lasing, especially in short wavelengths and strongly confined, highly multimode cavities, making it difficult to construct coherent high-power laser sources.
Innovation Solution
A semiconductor laser element is designed with a first ring resonator including a diffraction grating and a second ring resonator optically coupled by evanescent field coupling, both comprising semiconductor stacks with n-side and p-side layers and an active layer, where the second ring resonator amplifies light of the same peak wavelength as the first, enabling single-mode lasing and high power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single ring resonator with diffraction grating is used, then single-mode lasing is achieved, but the output power is limited
Solution Approach 1:
The patent combines two ring resonators into a coupled system where one resonator provides single-mode selection via diffraction grating while the other amplifies the light, merging the functions of mode control and power amplification into a unified device that achieves both single-mode operation and high output power
Solution Approach 2:
The laser system is segmented into two functionally distinct ring resonators: the first resonator with diffraction grating handles wavelength selection and single-mode operation, while the second resonator handles power amplification, allowing each component to optimize its specific function
2Power
If multiple ring resonators are coupled to increase power, then output power increases, but maintaining single-mode lasing becomes difficult
Solution Approach 1:
The patent merges multiple resonators into a coupled system where the first ring resonator with diffraction grating establishes single-mode operation and the second ring resonator amplifies this mode, combining mode selection and power amplification functions in an integrated structure
Solution Approach 2:
The first ring resonator with diffraction grating performs preliminary mode selection and wavelength filtering before the light enters the second resonator for amplification, establishing single-mode operation in advance to simplify the overall coupling structure
3Ease of manufacture
If evanescent field coupling is used to couple resonators, then optical coupling is achieved, but precise wavelength matching is required
Solution Approach 1:
The diffraction grating in the first ring resonator provides wavelength-selective feedback that reinforces the desired single-mode operation and suppresses other modes, creating a feedback mechanism that maintains wavelength matching between the coupled resonators
Solution Approach 2:
The patent uses diffraction grating parameters (pitch, depth, width) to precisely control the resonant wavelength of the first ring resonator, ensuring it matches the second resonator's wavelength and enabling effective evanescent field coupling
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 solution achieves high brightness and high power single-mode lasing, suitable for use in laser arrays and integrated photonic systems, maintaining single-mode operation even at higher pump powers beyond the lasing threshold.
Implementation Method 1
a second ring resonator optically coupled to the first ring resonator by evanescent field coupling
Implementation Method 2
the first ring resonator includes a diffraction grating. DFB ring resonators induce single-mode lasing, in which the single mode matches the diffraction grating pitch
Data Source
AI summary
A semiconductor laser element a first ring resonator. The first ring resonator includes a first semiconductor stack including a first n-side semiconductor layer, a first p-side semiconductor layer, and a first active layer located between the first n-side semiconductor layer and the first A-side semiconductor layer, wherein the first ring resonator comprises a diffraction grating. The semiconductor laser element further includes a second ring resonator optically coupled to the first ring resonator by evanescent field coupling. The second ring resonator includes a second semiconductor stack including a second n-side semiconductor layer, a second p-side semiconductor layer, and a second active layer located between the second n-side semiconductor layer and the second p-side semiconductor layer, wherein a peak wavelength of light emitted by the second ring resonator is the same as a peak wavelength of light emitted by the first ring resonator.