oa Fiber Optic Channel for Measuring Temperature and Pressure

This work is devoted to the development of a fiber optic channel for measuring temperature and pressure. The channel includes temperature and overpressure sensors, an interrogator and cable lines for signal transmission.

Pressure and temperature sensors are based on fiber Bragg gratings (FBG). To measure temperature in the range from -50 to +240°C, a single FBG is used. To measure pressure in the range from 0 to 20 MPa, an array of two FBGs is used (one directly for measurements, the second for temperature compensation).

The fiber optic interrogator is based on a vertical-cavity surface-emitting laser. The laser is powered by current pulses. The use of this mode of operation allows for controlled tuning of the wavelength of the generated radiation (range up to 4 nm). Analysis of the signals reflected from the FBG using a photodetector makes it possible to determine its resonant wavelength. These processes are controlled by FPGA. The number of interrogator channels is 8, the sampling frequency is up to 1 kHz.

The transmission of signals between the sensors and the interrogator is carried out using a special cable assembly. The assembly is implemented on the basis of an armored fiber optic cable and protected connectors.

The presented fiber optic channel for measuring temperature and pressure is used as part of complex systems in order to control their operating modes and control parameters.