Miniature Spectrometer Using Waveguide Array for Chip-Scale Design
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Solution Overview
Problem
Conventional spectrometers are bulky due to the need for a grating to split light, restricting the development of wrist-oriented noninvasive blood sugar sensors, which require significant space for light splitting and detection.
Innovation Solution
A miniature spectrometer design featuring a band-pass filter with an array of waveguides configured for surface plasmon mode transmission, utilizing a grating in-coupler and optical detectors integrated on a chip, allowing for compact light splitting and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a grating is used to split light in a conventional spectrometer, then light splitting and spectral analysis can be achieved, but the device becomes bulky and requires significant space
Solution Approach 1:
The spectrometer is segmented into multiple functional layers including a waveguide layer with multiple waveguides, each coupled to a specific detector. This segmentation allows the system to achieve spectral analysis through spatial separation of wavelength channels rather than using a bulk grating, thereby reducing overall device volume while maintaining measurement precision
Solution Approach 2:
The invention transitions from a conventional planar grating-based spectral splitting approach to a three-dimensional integrated photonic structure. Multiple waveguides are arranged in a layered configuration with detectors positioned at different spatial locations, enabling spectral analysis through vertical and lateral dimensionality rather than relying on a large horizontal grating area
2Measurement precision
If a bulky grating is used for spectral analysis, then resolution can be secured, but the spectrometer cannot be miniaturized for wrist-oriented applications
Solution Approach 1:
The design employs a nested structure where multiple waveguides are integrated within a compact layered architecture. Each waveguide is coupled to its corresponding detector in a nested arrangement, allowing the system to achieve sufficient spectral resolution through precise spatial coupling rather than requiring a long optical path from a large grating
3Measurement precision
If conventional spectrometer design is used, then spectral analysis function is achieved, but the device complexity and manufacturing difficulty increase for miniaturization
Solution Approach 1:
The waveguide layer serves multiple functions simultaneously: it acts as the optical coupling medium, provides spatial separation for different wavelengths, and integrates the detection interface. This multi-functionality eliminates the need for separate grating components and simplifies the manufacturing process while maintaining spectral analysis accuracy
Solution Approach 2:
The invention merges the functions of the grating, optical path, and detector array into a single integrated photonic structure. The waveguides directly couple incident light to detectors through their spatial arrangement, combining spectral splitting and detection functions into one manufacturable component that can be produced using standard photolithography techniques
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
Enables the miniaturization of spectrometers to a chip-scale format, facilitating their use in wrist-oriented noninvasive sensors by efficiently splitting light according to wavelengths, thus overcoming the size constraints of conventional spectrometers.
Implementation Method 1
a band-pass filter which is configured to transmit input light in a surface plasmon mode
Implementation Method 2
The in-coupler may include a grating in-coupler
Implementation Method 3
an array of optical detectors configured to detect respective lights output from a second end of the array of waveguides
Data Source
AI summary
A miniature spectrometer and a miniature spectrometer module employing the same are disclosed. The disclosed miniature spectrometer includes: a band-pass filter which is configured to transmit input light in a surface plasmon mode and which has an array of waveguides which are configured to output a plurality of different transmission wavelength bands; an in-coupler configured to couple the transmitted input light to a first end of the array of waveguides; and an array of optical detectors configured to detect respective lights which are output from a second end of the array of waveguides.