Fourier transform spectrometer on silicon substrate and method for obtaining reconstructed spectrum of light source

Abstract

The invention relates to a Fourier transform spectrometer on a silicon substrate and a method for obtaining a reconstructed spectrum of a light source. The spectrometer comprises a waveguide input coupler, a cascade optical switch, a non-equal-arm sub-wavelength grating (SWG) waveguide pair and a germanium-silicon detector, and the cascade optical switch is connected through the non-equal-arm SWGwaveguide pair. A series of non-equal-arm Mach-Zehnder interferometer (MZI) arrays with different optical path differences are formed by adjusting an optical switch state gating optical path, a Fourier transform spectrometer based on spatial heterodyne coherence is realized, and a spectrum is reconstructed by using a compressed sensing algorithm. Compared with a traditional passive MZI array structure, the chip size can be effectively reduced, and the number of sampling points is increased; wherein the unequal-arm SWG waveguide pair can effectively improve the temperature stability of the chipand expand the working bandwidth. According to the invention, the application requirements of the Fourier transform spectrometer on miniaturization and portability can be met, and the problem that the spectrometer on the existing silicon substrate is generally sensitive to temperature can be solved.

Description

technical field [0001] The invention belongs to the field of light detection and sensing, in particular to a Fourier transform spectrometer on a silicon substrate and a method for obtaining light source reconstruction spectrum. Background technique [0002] Infrared spectrometer uses the absorption characteristics of infrared radiation of different wavelengths to realize the analysis and identification of molecular structure and chemical composition, which is one of the most effective means of chemical analysis. Traditional Fourier transform spectrometers, such as Michelson interferometers, change the optical path difference of two beams of light by moving mirrors to generate interference fringes, and use fast Fourier transform to decode them. The longer the optical path difference, the higher the spectral measurement accuracy. Traditional desktop Fourier transform spectrometers generally need to work in a laboratory environment, and the optomechanical movement modules in t...

AI Technical Summary

Problems solved by technology

However, the power consumption of SHS based on active optical path difference modulation is relatively high, and the resolution is only on the order of nm; for SHS based on asymmetric MZI arrays, the number of effective spectral resolution points is related to the number of MZIs, so it is difficult to balance large bandwidth and high resolution. resolution

In addition, the influence of ambient temperature on the on-chip Fourier transform spectrometer also greatly limits its practical application.

In short, the existing on-chip Fourier transform spectrometer has a large gap with the existing advanced desktop Fourier transform spectrometer in terms of effective resolution points, spectral range and practicality.

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