MZ interference evanescent wave 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 core and fibre covering on one piece of fibre to form a MZ interferometer and then placing a film layer sensitive to chemical or biological molecule on fibre covering surface to form evanescent wave transducer of fibre MZ interferometer structure. The sensing system comprises light source of wide band, optical fibre, chemical and biological transducer of evanescent wave and MZ interference in optical microstructure, 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 microstructure MZ interference type evanescent wave chemical and biological sensor and system. 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, Antibodies, nucleic acids, DNA, animal and plant tissues or cells, microorganisms, polymer materials, etc., sensitive membranes, sol-gels or themselves, adsorbed, solidified or installed on optical fibers, planar optical waveguides, capillary waveguides, and the to-be-treated samples in the sample Selective chemical or biomolecular recognition of the detected substance, and then converted into various optical information, so as to obtain chemical and biological information. In most sensors, the opt...

AI Technical Summary

Problems solved by technology

[0008] At present, the optical fiber evanescent wave biosensor still has some disadvantages: (1) The fabrication of the sensor is cumbersome and difficult, and the optical fiber cladding needs to be removed by chemical corrosion or abrasion, and the removal position of the optical fiber cladding is difficult to precisely control

At the same time, the surface of the fiber core after chemical corrosion or abrasion of the fiber cladding is a rough non-optical interface, which affects the optical performance at the interface, and the noise of the signal light is very large, which affects the measurement accuracy

(2) The sensing system uses a 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 reliability and accuracy of the sensing system, and it is difficult to achieve higher precision biomolecular measurement and measurement. analyze

(3) The influence of stray light interference is great, and stray light outside the fiber core can also excite fluorescence, thereby affecting the detection results, so it is necessary to shield stray light

(4) The data has no fault tolerance, and the sensing system has no telemetry capability

The optical fiber used in the method and its system is a section of multimode optical fiber with a length of about 40cm and an outer diameter of 1mm. This section of optical fiber is only used as a sensing head, and it is not used as a transmission medium, and the advantages of the optical fiber are not fully utilized.

(5) 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 system structure is complex and huge, and alignment and debugging are very difficult. Interference has a big impact

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

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