MZ interference SPR chemical and biological sensor and system with fibre-optical microstructure

Abstract

A chemical and biological transducer is prepared by setting two long period fibre gratings, fibre covering and fibre core on one piece of fibre to form a MZ interferometer and then plating a metal film on fibre covering surface to form SPR transducer of fibre MZ interferometer structure. The sensing system comprises wide band light source, fibre, chemical and biological transducer formed as above, fibre spectrograph and computer as said transducer is set in gas or solution of chemical composition or biological molecule to be tested.

Description

technical field [0001] The invention belongs to the technical fields of optical fiber sensing, biology and chemistry, and in particular relates to an optical fiber microstructure MZ interference type SPR chemical and biological sensor and a system thereof. Background technique [0002] Optical fiber biological and chemical sensor is a new type of sensing technology that was born in the mid-1970s. , nucleic acid, DNA, animal and plant tissues or cells, microorganisms, polymer materials and other sensitive membranes, sol-gel or itself, adsorbed, solidified or installed on optical fibers, planar optical waveguides, capillary waveguides, and detect substances in samples Perform selective absorption (adsorption) or recognition, and then convert into various optical information, such as absorption, reflection, fluorescence, phosphorescence, chemiluminescence and bioluminescence, Raman scattering, photoacoustics and surface plasmons of ultraviolet, visible and infrared light Reson...

AI Technical Summary

Problems solved by technology

[0016] There are also some defects in this type of sensor and system: (1) The prism-type sensor head is complex and bulky

The production of the optical fiber sensor head is cumbersome and difficult, and the cladding needs to be removed by chemical corrosion or mechanical abrasion, and the removal position or size of the cladding is difficult to precisely control

It is also difficult to fabricate a metal diffraction grating type sensor head

(2) The stability of the system is poor: whether it is wavelength modulation or angle modulation method, the signal detected directly is the light intensity, and it is the light intensity of a single optical path

The fluctuation and interference of the light source, optical path and circuit system have a great impact on the sensing system, reducing the reliability and accuracy

In the existing single light path intensity detection, this effect is difficult to eliminate

(3) Strong stray light interference: In the three SPR sensors of prism type, metal grating type and fiber optic type, stray light can enter the optical path and detector

(4) For fiber optic sensors, after chemical corrosion or mechanical abrasion of the cladding, there will be a rough interface, and it is difficult to obtain a smooth optical surface of the fiber core, which will affect the total reflection characteristics irregularly and generate large noise signals. Significantly reduced signal-to-noise ratio

(5) The data has no fault tolerance: the data obtained by the existing sensing system has no redundant information, and when there is a large interference and error, it will seriously affect the accuracy of the test or analysis results

(6) Weak telemetry capability: Prism-type and metal grating-type SPR sensors are difficult to achieve telemetry through optical fibers; at present, the optical fibers used in fiber-optic SPR sensors are mainly multi-mode fibers with large core diameters (small-core-diameter optical fiber sensors are difficult to manufacture, or even impossible) Production), generally only use a section of optical fiber of about tens of centimeters as the sensing head, it is difficult to make full use of the advantages of optical fiber

(7) The structure of the sensing system is complex and huge, and the operation is not flexible enough. Both the prism type and the metal grating type SPR sensor need a flow cell

The environmental adaptability is poor, the temperature change has a great influence on the test results, and the interference from the external vibration is also great, so it is very difficult to align and debug, and the same is true for the existing optical fiber sensors

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