QUASI-DISTRIBUTED RECIRCULATED FIBER OPTIC GASEOUS OXYGEN MEASUREMENT SYSTEM

A scheme of a quasi-distributed fiber-optic system for monitoring the oxygen concentration of the recirculation type is proposed. The principle of measurement is to register changes in the recirculation frequency of single optical pulses with periodic regeneration simultaneously at several wavelengths. The operation of the sensor is based on a change in the length of the magnetostrictive strips and the segments of optical fibers associated with them under the influence of a changing magnetic field due to the paramagnetic properties of gaseous oxygen. The numerical estimation of the measurement error has been carried out. It is shown that with a length of the sensitive element of the sensor of 1.5 m and a radius of 0.6 ... 0.7 m, it is possible to obtain a relative error of the measurement method no worse than 0.6% for pure oxygen and 2.5% for an air mixture.