Refractive index sensing device based on few-mode silicon nitride micro-ring resonator

Abstract

The invention discloses a refractive index sensing device based on a few-mode silicon nitride micro-ring resonator. The few-mode silicon nitride micro-ring resonator comprises a plurality of waveguideunits which are arranged in parallel, and each unit is composed of a single single-mode straight waveguide used for input and output and a single few-mode annular waveguide used for resonance. The straight waveguides and the annular waveguides in the units are arranged on the same plane and do not make contact with each other, the straight waveguides between the units are parallel, and the two ends of each single-mode straight waveguide serve as the input end and the output end respectively. A single straight waveguide structure and a single annular waveguide structure of the all-pass type micro-ring resonator are adopted to support at least one mode, resonance peaks corresponding to a fundamental mode and a high-order mode can be generated in a transmission spectrum, drifts of optical fields in different modes on refractive index changes are different, and therefore refractive index sensing measurement can be conducted by means of the characteristic.

Description

technical field [0001] The invention relates to a technology in the field of refractive index sensing, in particular to a refractive index sensor which adopts a few-mode microring resonator structure manufactured by an SOI method and uses a wavelength detection method for sensing and detection. Background technique [0002] The refractive index sensor is a device that can sense the change of the refractive index near the waveguide and convert it into a change of the output optical properties. According to the different sensing principles, it is divided into intensity detection and wavelength detection. The former is by detecting the transmission spectrum. Before and after the change of refractive index, the change of light intensity at the same wavelength is used for sensing and detection. The microring waveguide used in this method has a high quality factor, but since this method can only be detected near the resonance peak, the detection limit High, narrow dynamic range. ...

AI Technical Summary

Problems solved by technology

[0002] The refractive index sensor is a device that can sense the change of the refractive index near the waveguide and convert it into a change of the output optical properties. According to the different sensing principles, it is divided into intensity detection and wavelength detection. The former is by detecting the transmission spectrum. Before and after the change of refractive index, the change of light intensity at the same wavelength is used for sensing and detection. The microring waveguide used in this method has a high quality factor, but since this method can only be detected near the resonance peak, the detection limit high, narrow dynamic range

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