Analytical method of series-connection LPWG (Long Period Waveguide Grating) biochemical sensor

Abstract

The invention discloses an analytical method of a series-connection LPWG (Long Period Waveguide Grating) biochemical sensor. The coupling property of the LPWG is utilized to enable light in a certain bandwidth range by taking the resonant wavelength as a center in incident light wavelength to enter a tested cladding layer through coupling of the LPWG 1, then the light is coupled by LPWG2 and is enabled to enter a waveguide core layer, and then the light and fundamental modes transmitted in the same direction in the waveguide core layer are interference-output; when a tested substance is changed, resonant wavelength in the output spectrum is offset, and the offset can be detected and the concentration of the tested substance can be calculated; and an absorption spectrum signal of liquid in the output spectrum is analyzed and the tested substance is qualitatively analyzed. According to the analytical method, the problem that the traditional biochemical sensor adopts a specific sensitive film having high cost and single detection index for qualitative analysis is solved; and besides, the problem that the limited bandwidth caused by a water absorption band is required to be avoided in the quantitative determination of water-containing liquid is solved.

Description

technical field [0001] The invention belongs to the fields of integrated optics, biophotonics and spectrum analysis, and specifically relates to the mode coupling and transmission characteristics of long-period waveguide gratings, and qualitative and quantitative analysis models and methods in biochemical sensing mechanisms. Background technique [0002] At present, for the biochemical sensors developed at home and abroad, whether they are based on electrochemical principles, microfluidic technology or optical principles for detection, biochemical sensitive films are usually deposited on the contact surface between the device and the measured substance. The adsorption of specific substances by the membrane or the physical and chemical changes with them are used to select and distinguish the measured substances, and larger prisms and optical circulators are required. This design scheme not only increases the design complexity of the device, but also increases the size and cos...

AI Technical Summary

Problems solved by technology

Usually the substance to be detected needs to be sent into the detection area through water as a solvent and as a carrier. If the selected detection light source band contains the absorption information of water, the quantification cannot be completed or will have a great impact on the quantitative results.

In this case, only the detection light source of a specific wavelength band can be selected, which limits the detection range

Especially in the mid- and far-infrared bands, the fundamental frequency absorption information of almost all substances (including biochemical gases and liquids) is in the mid- and far-infrared bands, and the absorption coefficient of substances is 1 to 2 orders of magnitude larger than that in the near-infrared band, which will greatly improve the detection sensitivity. , however, in the mid-to-far infrared band, the absorption of water is very strong, the emergence of this challenging problem brings great troubles to biochemical detection

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