Optical Biosensor Grating Couplers for CMOS Light Routing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current optical biosensors face challenges in efficiently coupling and processing light patterns for effective biomaterial sensing, particularly in integrating grating couplers for input and output terminals with photoelectric conversion devices.
Innovation Solution
The optical biosensor design incorporates a first grating coupler for inputting light patterns to the front side and a second grating coupler for outputting these patterns to a photoelectric conversion device at the rear, with both couplers having the same depth and the optical biosensor including a light resonator and optical spectrometer for biomaterial sensing, utilizing materials like Si, Si3N4, and polymers, and employing chemical mechanical polishing for manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light patterns are coupled through multiple layers to reach photoelectric conversion devices at the rear side, then sensing efficiency is improved, but manufacturing complexity increases due to precise depth alignment requirements
Solution Approach 1:
The patent makes the depths of the first and second grating couplers equal, creating a symmetric structure where both couplers are etched to the same depth within the first and second layers. This equipotential approach simplifies manufacturing by eliminating the need for complex depth alignment procedures while maintaining efficient light coupling to the rear-side photoelectric conversion devices.
Solution Approach 2:
The grating couplers are embedded within multiple layers (first layer and second layer) in a nested configuration, where the couplers are integrated into the layered structure rather than being added as separate components. This nesting approach streamlines manufacturing by incorporating the coupling function directly into the existing layer stack.
2Reliability
If grating couplers are integrated within multiple layers, then light coupling efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
By setting the depths of both grating couplers to be equal, the patent creates a symmetric structure that is inherently more robust to manufacturing variations. This approach maintains high light coupling efficiency while reducing the stringency of depth alignment precision requirements compared to asymmetric designs.
Solution Approach 2:
The patent optimizes the etch depth parameter of the grating couplers by making them equal, which changes the manufacturing parameters from requiring precise differential depth control to requiring only matched depth control. This parameter change maintains coupling efficiency while relaxing precision requirements.
3Measurement precision
If the optical biosensor includes light resonators and optical spectrometers, then biomaterial sensing capability is enhanced, but device structure becomes more complex
Solution Approach 1:
The grating couplers are designed to serve multiple functions: they couple light into the waveguide, enable resonance excitation in the light resonator for sensing, and facilitate light extraction to the photoelectric conversion devices. This multi-functionality enhances biomaterial sensing capability while avoiding the need for separate coupling structures, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent combines the light coupling function with the resonance excitation function by integrating the grating couplers directly with the light resonator structure. This merging of functions enhances sensing capability through resonance while maintaining a compact device structure, as the same grating structure serves both purposes.
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 configuration enhances the sensing speed and efficiency of biomaterial detection by directly coupling light to the CMOS image sensor, simplifying the system structure and reducing its size while maintaining precise control over light patterns.
Implementation Method 1
a first grating coupler of an input terminal, the first grating coupler being configured to couple a light pattern provided to a front side of the optical biosensor
Implementation Method 2
a second grating coupler of an output terminal configured to output a light pattern, the second grating coupler being coupled to the first grating coupler and being configured to couple a light pattern to a photoelectric conversion device formed at the rear of the optical biosensor
Implementation Method 3
photoelectric conversion device formed at the rear of the optical biosensor
Data Source
AI summary
An optical biosensor, and a method of manufacturing the same, includes a first layer, a second layer stacked on the first layer, a first grating coupler within the first layer and the second layer, and a second grating coupler within the first layer. The first grating coupler is configured to couple a light pattern provided to a front side of the optical biosensor. The second grating coupler is configured to output the light pattern coupled by the first grating coupler to a photoelectric conversion element on a rear side of the optical biosensor.