SYSTEM FOR DETERMINING THE CENTRAL WAVELENGTH OF FIBRE-OPTIC SENSORS Russian patent published in 2022 - IPC G01B11/16 

FIELD: measuring equipment.

SUBSTANCE: invention relates to measuring equipment and can be used in the field of measuring various physical quantities, such as strain, temperature, pressure, etc., using fibre-optic sensors, e.g., in systems for monitoring the strain of articles made of composite materials, at power supply facilities, engineering and other structures. Claimed system for determining the central wavelength of fibre-optic sensors comprises a laser radiation source, an optical splitter, an optical sensor, a first photodetector, and a second photodetector. The laser radiation source is linked with the input of the optical splitter by means of a fibre light guide, the second output of the optical splitter is linked with the input of the optical sensor by means of a fibre light guide; an optical coupler, a circulator, an optical filter, N optical splitters series-connected by fibre light guides, N optical sensors, and N optical connectors series-connected by fibre light guides, wherein N is a natural number and N≥1. Herewith, the first output of each last of the N optical splitters is linked with the input of each corresponding next of the N optical splitters, the second output of each of the N added optical splitters is linked with the input of the corresponding one of the N optical sensors by means of a fibre light guide, the output of each of the N optical sensors is linked with the second input of the corresponding one of the N optical connectors by means of a fibre light guide. The first input of each last of the N optical connectors is linked with the output of each corresponding next of the N optical connectors, the output of the first of the N optical connectors is linked with the input of the optical coupler by means of a fibre light guide, the first output of the optical coupler is linked with the input of the first photodetector by means of a fibre light guide, the second output of the optical coupler is linked with the input of the circulator by means of a fibre light guide, the first output of the circulator is linked with the optical filter by means of a fibre light guide, the second output of the circulator is linked with the input of the second photodetector by means of a fibre light guide, and the outputs of the first and second photodetectors are linked with the first and second inputs of the controller for determining the central wavelength of optical sensors by means of electrical wires, respectively. The laser radiation source is made broadband, and each of the optical sensors is based on a fibre Bragg grating with two phase shifts. The system additionally includes a second circulator, a second optical filter with a dependence of the position of the central wavelength on the temperature different from that of the first optical filter and located in close proximity to the first optical filter, and a third photodetector. Herewith, the third output of the optical coupler is linked with the input of the second circulator by means of a fibre light guide, the first output of the second circulator is linked with the second optical filter by means of a fibre light guide, the second output of the second circulator is linked with the input of the third photodetector by means of a fibre light guide, and the output of the third photodetector is linked with the third input of the controller for determining the central wavelength of optical sensors by means of electrical wires.

EFFECT: simpler implementation of a fibre-optic measuring system with a simultaneous increase in the range of working temperatures of the system.

4 cl, 6 dwg