Interference evanescent wave chemical and biological sensor and system with fibre-optical Michelson

Abstract

A chemical and biological transducer is prepared by setting long period fibre grating, reflecting film on fibre section, fibre covering and fibre core on one piece of fibre to for a Michelson interferometer and then forming a fibre evanescent wave chemical and biological transducer based this interferometer. The sensing system comprises wide band light source, fibre, chemical and biological transducer formed as above, wide band coupler, fibre spectrograph and computer.

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 micro-Michelson interference evanescent wave chemical and biological sensor and a system thereof. Background technique [0002] Optical fiber chemical and biological sensors are a new type of sensing technology that was born in the mid-1970s. This sensor is an indicator dye, enzyme, coenzyme, biological receptor, antigen, etc. , antibodies, nucleic acids, DNA, animal and plant tissues or cells, microorganisms, polymer materials, etc., sensitive membranes, sol-gels or themselves are adsorbed, solidified or installed on optical fibers, planar optical waveguides, and capillary waveguides. Selective identification of measured substances, and then converted into various optical information, such as absorption, reflection, fluorescence, phosphorescence, chemiluminescence and bioluminescence, Raman scattering, photoacous...

AI Technical Summary

Problems solved by technology

[0008] At present, there are still many shortcomings and deficiencies in optical fiber evanescent wave chemical and biological sensors, mainly as follows: (1) The production of the sensing head is cumbersome and difficult: the optical fiber sensing head needs to remove the cladding by chemical corrosion or mechanical abrasion , it is difficult to precisely control the removal position or size of the cladding; in addition, after chemical corrosion or mechanical abrasion of the cladding, it is difficult to obtain a smooth optical surface of the fiber core, and a rough interface will appear, thereby affecting the total reflection characteristics of light at the interface or other optical properties

(2) The measurement accuracy is low: due to the single optical path intensity measurement method, the fluctuation and interference of the light source, optical path and circuit system have a great impact on the sensing system, such as the instability of the driving circuit, the aging or drift of the light source, The bending of the optical fiber, the fluctuation of the optical path environment, the drift and instability of the detection system will reduce the reliability and accuracy of the measurement data

When the external stray light changes, the fluorescent signal obtained by the detector will inevitably change, thus affecting the detection accuracy

(4) The data has no fault tolerance: the fluorescence information obtained by the existing method mainly includes intensity and time, and it is simple data, there is no redundant information, and the amount of data information is small

When one or a group of data collected has large interference and errors, it will seriously affect the accuracy of test or analysis results

Therefore the method is not fault tolerant

(5) No telemetry capability: The optical fiber used in this method and its system is a multimode optical fiber with an outer diameter of 1 mm, which has a large mode loss, a larger outer diameter of the optical fiber, and cannot be bent. Without using an optical fiber as a transmission medium, it is difficult to transmit light over a long distance signal, only a small section (about tens of centimeters) of optical fiber is used as the sensing head, and it is difficult to make full use of the advantages of optical fiber

(6) The system structure is complex: the sensing system does not use modern optical miniaturization and fiber optic technology, but uses conventional optical components to form the system

The structure of the photoelectric detection and processing system to meet this requirement is very complex and large

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