Bichromatic Grating Coupler for Atomic Sensor Alignment
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Solution Overview
Problem
Current atomic sensor optical systems face challenges in mass production due to the need for precise alignment of bulk optical components, which is costly and difficult to validate before fixing positions relative to the ultra-high vacuum cell chamber, and lack a method for projecting multiple wavelengths of light from a single emission point compatible with integrated waveguide optical systems.
Innovation Solution
A bichromatic grating coupler with a two-dimensional diffraction grating structure comprising superimposed sub-gratings allows for the efficient projection of multiple wavelengths of light into overlapping regions, ensuring zero cross-talk and independent control of beam directions, facilitating the use of integrated photonic circuits and reducing the need for bulk optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If bulk optical components are used for precise beam control, then beam alignment precision is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent combines multiple optical functions (diffraction, polarization control, beam direction) into a single integrated grating coupler structure. The superimposed first and second gratings are fabricated together on the same substrate, merging what would traditionally require separate bulk optical components into one monolithic device, thereby reducing complexity while maintaining precision
Solution Approach 2:
The patent replaces mechanical alignment of bulk optical components with a lithographically defined grating structure. The precise beam control previously achieved through mechanical positioning of lenses and mirrors is now achieved through the fixed geometric patterns of the grating, eliminating the need for complex mechanical adjustment mechanisms
2Manufacturing precision
If bulk optical components are aligned one at a time, then beam parameter matching is improved, but mass production efficiency decreases
Solution Approach 1:
The patent segments the optical functionality into distinct grating regions (first and second gratings) that can be independently designed for specific wavelengths and beam parameters, yet are fabricated together in a single batch process. This allows customization for different beam requirements while maintaining mass production efficiency
Solution Approach 2:
The patent enables independent control of beam parameters (wavelength, direction, polarization) through the grating design parameters (period, orientation, depth) rather than through physical adjustment during assembly. This allows all beams to be precisely matched during fabrication rather than requiring time-consuming post-assembly alignment
3Adaptability or versatility
If multiple wavelengths are projected from separate points, then wavelength independence is improved, but beam overlap precision decreases
Solution Approach 1:
The patent merges multiple wavelength handling functions into a single grating coupler structure where first and second gratings are superimposed. This ensures that all wavelength-specific beams originate from the same physical location (the grating structure itself), guaranteeing perfect spatial overlap while maintaining wavelength independence through the distinct grating patterns
4Volume of moving object
If integrated waveguide optical systems are used, then device compactness is improved, but manufacturing compatibility decreases
Solution Approach 1:
The patent creates a universal grating coupler structure that serves multiple functions: it acts as both a waveguide interface and a diffraction element, and can handle multiple wavelengths simultaneously. This multi-functionality is achieved through a single fabrication process that is compatible with standard integrated photonics manufacturing, eliminating the need for separate components
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 approach enables the production of more robust, compact, and cost-effective atomic sensors by ensuring precise alignment and overlap of laser beams, enhancing the performance of sensors like optical lattice clocks by allowing perfect overlap of trapping beams and improving manufacturing efficiency.
Implementation Method 1
a first light beam having a first wavelength is diffracted in a first direction by the first sub-grating. The second optical port is configured to direct a second light beam having a second wavelength to the diffraction grating structure, such that the second light beam is diffracted in a second direction by the second sub-grating
Data Source
AI summary
A bichromatic grating coupler comprises a two-dimensional diffraction grating structure, including a first sub-grating having a first periodic structure and a second sub-grating having a second periodic structure. The first and second sub-gratings are superimposed with respect to each other in the diffraction grating structure. A first optical port is coupled to the diffraction grating structure along a first direction, and a second optical port is coupled to the diffraction grating structure along a second direction. The first optical port is configured to direct a first light beam having a first wavelength to the diffraction grating structure, such that the first light beam is diffracted in a first direction by the first sub-grating. The second optical port is configured to direct a second light beam having a second wavelength to the diffraction grating structure, such that the second light beam is diffracted in a second direction by the second sub-grating.