Random-Defect Waveguide Spectrometer for Compact Spectrum Reconstruction
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Solution Overview
Problem
Existing spectrometers are large, costly, and inconvenient to carry due to their reliance on grating dispersion and Fourier transform, limiting their application in compact and portable devices.
Innovation Solution
A spectrometer apparatus utilizing defect scattering calculation and reconstruction, employing a light scattering system with a multi-mode waveguide and random defect scattering array, coupled with a photodetector, to achieve high-resolution spectral analysis without traditional light-splitting elements, reducing device count and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional grating dispersion and Fourier transform methods are used in spectrometers, then spectral analysis capability is achieved, but device size becomes large and portability is poor
Solution Approach 1:
The patent replaces traditional mechanical optical components (gratings, prisms, mirrors) with an integrated photonic chip that uses waveguide-based light propagation and defect scattering. This substitution of mechanical dispersion systems with integrated photonic structures enables spectral analysis while dramatically reducing device size to chip-scale dimensions.
Solution Approach 2:
The patent implements a nested structure where the photodetector is integrated directly onto the waveguide chip, with the detection system embedded within or adjacent to the light scattering system. This nesting of detection functionality within the optical path eliminates separate external components and achieves compact integration.
2Measurement precision
If traditional spectrometer components are used, then spectral detection is achieved, but manufacturing cost and maintenance cost become high
Solution Approach 1:
The patent merges multiple discrete optical components (light source coupling, waveguide, defect scattering elements, and photodetector) into a single integrated photonic chip. This consolidation eliminates the need for separate manufacturing and assembly of multiple precision optical components, significantly reducing manufacturing complexity and maintenance requirements.
Solution Approach 2:
The patent changes the operational parameters from traditional bulk optics to integrated photonic parameters, using sub-wavelength defect structures (dimensions much smaller than operating wavelength) to create scattering effects. This parameter change enables fabrication using standard semiconductor processing techniques rather than precision optical machining.
3Measurement precision
If high precision optical components are used in traditional spectrometers, then spectral analysis accuracy is improved, but device complexity and size increase
Solution Approach 1:
The patent introduces localized defect structures with specific geometric properties (size, shape, distribution) at particular locations within the waveguide to create controlled scattering effects. These local defect characteristics are optimized to achieve spectral resolution without requiring high precision across the entire optical system.
Solution Approach 2:
The patent uses computational methods to create a digital model (transmission matrix) of the defect scattering system during calibration, then uses this copied model to reconstruct spectra from detector signals. This computational copying replaces the need for physically complex precision optical 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
The apparatus achieves high-resolution spectral analysis with a compact, portable design, low manufacturing precision requirements, and reduced cost, suitable for mass production.
Implementation Method 1
surface defects are used to obtain scattered light
Implementation Method 2
the photodetector is arranged on the optical waveguide and is used to detect scattered light
Implementation Method 3
the width of the single-mode waveguide satisfies that light propagation on an operating band of a spectrometer is single-mode
Implementation Method 4
the multi-mode interference mainly occurs in a transverse direction of the waveguide
Data Source
AI summary
An apparatus and method for spectrum detection by defect scattering calculation and reconstruction. The apparatus includes a photodetector, a light input system, a multi-mode waveguide, a random defect scattering structure and a substrate. The defect scattering structure is a recess with random quantities of size and position on the surface of the optical waveguide. The technical solution reconstructs a target spectrum by introducing random defects onto the surface of the optical waveguide to obtain scattered light, has the advantages of fewer devices, compact spatial optical path and small size compared with the traditional commercial spectrometer, effectively reduces the system complexity and cost of the spectrometer, and improves the portability of the spectrometer. This structure can reproduce an incidence spectrum well when using the calculation and reconstruction method to reconstruct the spectrum, and has a large bandwidth and high spectral resolution.