Dual Coupler Device for Polarization-Specific Light Detection
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Solution Overview
Problem
Current non-invasive biometric sensors face challenges in efficiently measuring biometric signals, particularly in mobile devices, due to limitations in coupling and analyzing lights of different polarization components, which affects the accuracy and efficiency of spectrum analysis.
Innovation Solution
The implementation of dual coupler devices in silicon photonics-based spectrometers, featuring a first and second coupler layer with perpendicular polarization directions, buried in a transparent dielectric layer, and equipped with grating-type couplers and reflectors to enhance wavelength selectivity and coupling efficiency, allowing for the independent optimization of p-polarization and s-polarization component reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single coupler layer is used to receive incident light, then the device structure is simple, but the coupling efficiency for lights of different polarization components is insufficient
Solution Approach 1:
The single coupler layer is divided into two separate coupler layers, each optimized for a specific polarization component (p-polarization and s-polarization). This segmentation allows each layer to independently maximize coupling efficiency for its designated polarization without compromise, resolving the contradiction between structural simplicity and coupling efficiency.
Solution Approach 2:
The solution transitions from a single-layer structure to a multi-layer structure with perpendicular polarization directions. By adding the dimensional aspect of polarization separation, the system achieves superior coupling efficiency for both polarization components while maintaining a relatively compact integrated structure.
2Reliability
If dual coupler layers with perpendicular polarization directions are used, then the coupling efficiency for different polarization components is improved, but the device complexity increases
Solution Approach 1:
The two coupler layers with different polarization selectivities are merged into a single integrated device structure with a shared substrate and coordinated design. This merging approach allows the complex dual-layer structure to function as a unified component, achieving high coupling efficiency while controlling overall device complexity through integrated design.
Solution Approach 2:
The dual coupler layer structure is designed to simultaneously handle both p-polarized and s-polarized light components within a single device. This multi-functionality allows the device to efficiently process all incident light polarizations without requiring separate devices, thereby improving coupling efficiency while managing complexity through universal design.
3Ease of manufacture
If conventional spectrometer structures are used, then the manufacturing process is simple, but the spectrum analysis accuracy and resolution are limited
Solution Approach 1:
The coupler layers are designed with spatially varying properties, including position-dependent coupling strengths and polarization-selective grating structures. This local quality optimization allows different regions of the coupler layers to be tailored for specific wavelength ranges and polarization components, thereby enhancing spectrum analysis accuracy and resolution while maintaining compatibility with standard manufacturing processes.
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 improves the coupling efficiency and accuracy of spectrum analysis, enabling miniaturization and high-resolution biometric measurements, such as blood sugar monitoring in mobile devices, by effectively handling lights of different polarization components.
Implementation Method 1
The first coupler layer and the second coupler layer may each include a grating-type coupler having a periodic grating structure. The periodic grating structure of the first coupler layer may be configured to have selectivity with respect to the light of the first polarization component, and the periodic grating structure of the second coupler layer may be configured to have selectivity with respect to the light of the second polarization component.
Implementation Method 2
The reflector may be disposed apart from the first coupler layer by a first distance that creates destructive interference with the light of the second polarization component and constructive interference with the light of the first polarization component in the first coupler layer. The reflector may be disposed apart from the second coupler layer by a second distance that creates destructive interference with the light of the first polarization component and constructive interference with the light of the second polarization component in the second coupler layer.
Implementation Method 3
The first coupler layer and the second coupler layer may have a higher refractive index than the transparent dielectric layer.
Data Source
AI summary
Provided are a dual coupler device configured to receive lights of different polarization components, a spectrometer including the dual coupler device, and a non-invasive biometric sensor including the spectrometer. The dual coupler device may include, for example, a first coupler layer configured to receive a light of a first polarization component among incident lights. and a second coupler layer configured to receive a light of a second polarization component among the incident lights, wherein a polarization direction of the light of the first polarization component is perpendicular to a polarization direction of the light of the second polarization component. The first coupler layer and the second coupler layer may be spaced apart from each other and extended along a direction in which the light propagates in the first coupler layer and the second coupler layer.