Resonant Waveguide Grating Laser Wavelength Stabilization
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Solution Overview
Problem
Existing laser systems for wavelength stabilization are costly due to the use of expensive materials like volume Bragg gratings.
Innovation Solution
A laser system utilizing a resonant waveguide grating as a feedback element, which is cost-effective and has a narrow band, allowing for precise wavelength definition, with features such as multiple periodicity, polarization dependence, and low absorption, to stabilize the wavelength of semiconductor lasers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If volume Bragg grating is used for wavelength stabilization, then wavelength stability is achieved, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive volume Bragg gratings with inexpensive planar waveguide gratings that can be manufactured using standard semiconductor fabrication techniques. The waveguide grating structure uses common materials and processes, making it a cost-effective alternative while maintaining the wavelength stabilization function.
Solution Approach 2:
The patent changes the fundamental parameters of the grating structure from three-dimensional volume Bragg gratings to two-dimensional planar waveguide gratings. This parameter change includes modifying the grating geometry, material composition, and fabrication method, thereby reducing cost while preserving the essential wavelength selection capability.
2Measurement precision
If resonant waveguide grating with narrow band is used, then wavelength definition precision is improved, but angular acceptance range is reduced
Solution Approach 1:
The patent introduces multiple periodicity in the waveguide grating structure, creating variations in the lateral dimension. This allows the grating to accept a broader range of incident angles by providing multiple reflection paths, thereby compensating for the naturally narrow angular acceptance of resonant waveguide gratings while maintaining wavelength precision.
Solution Approach 2:
The waveguide grating is designed with multiple periodic structures rather than a single uniform period. This segmentation into multiple grating periods with different spacings enables the system to handle a wider angular range of incident light while still providing precise wavelength definition through the resonant properties of each grating element.
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 resonant waveguide grating effectively stabilizes the wavelength of semiconductor lasers with minimal back reflection, enabling efficient and cost-effective wavelength stabilization while maintaining high reflectivity and low absorption, thus improving the laser system's performance and reducing costs.
Implementation Method 1
the feedback element is a resonant waveguide grating that reflects back a part of the laser radiation field that is within an angular acceptance range
Implementation Method 2
the resonant waveguide grating has waveguide layers applied to a substrate
Implementation Method 3
a resonant waveguide grating that reflects back a part of the laser radiation field that is within an angular acceptance range
Data Source
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AI summary
The invention relates to a laser system comprising at least one externally stabilized semiconductor laser (1), out of the active laser zone (11) of which a laser radiation field (20) can be coupled, a feedback element (50) disposed externally in the laser radiation field, wherein said feedback element couples a feedback radiation field (42) having a defined wavelength and bandwidth out of the laser radiation field, and back into the active laser zone for determining the wavelength and bandwidth of the laser radiation field, to be improved such that the wavelength stabilizer can be implemented more cost-effectively, wherein according to the invention the feedback element is a resonant waveguide grating reflecting back a part of the laser radiation field present within an angle acceptance range.