Optical switch loss measurement and calibration method in a distributed optical fiber temperature measuring device

Abstract

The invention relates to a method for measuring and calibrating optical switch loss in a distributed optical fiber temperature measuring device. The method includes: 1) collecting Stokes light at a position with a distance of 1 from the starting position of temperature measurement at a set temperature signal and the anti-Stokes optical signal, l is greater than the distance between the position of the optical switch and the temperature measurement initial position; 2) according to the temperature demodulation formula and the Stokes optical signal and anti-Stokes optical signal collected in step Tox light signal, calculate the calibration temperature T 0 The ratio of the actual Stokes light signal to the anti-Stokes light signal; 3) according to the calibration temperature T 0 The initial value of the ratio of the two curves of lower Stokes and anti-Stokes light and the ratio calculated in step 2) to obtain the optical switch loss coefficient. The calibration method is: using the above measurement method to obtain the loss coefficient of the optical switch, and using the loss coefficient of the optical switch to correct the calibration curve after the optical switch of the distributed optical fiber temperature measuring device. The invention improves the temperature measurement accuracy of each point along the temperature optical fiber.

Description

technical field [0001] The invention belongs to the field of distributed optical fiber temperature measurement systems, and in particular relates to a method for measuring and calibrating optical switch loss in a distributed optical fiber temperature measurement device. Background technique [0002] The distributed optical fiber temperature measurement device uses the entire temperature measurement optical fiber as a sensor, which can test the real-time temperature of all points along the line. As an important indicator of optical fiber temperature measurement, temperature accuracy requires that all points along the optical fiber must meet the standard requirements. According to the temperature demodulation formula: [0003] [0004] Among them, T is the temperature to be measured at a certain position along the optical fiber, and T 0 is the actual temperature at the calibration position (that is, the calibration fiber), that is, the calibration temperature, K B is Bol...

AI Technical Summary

Problems solved by technology

[0009] Aiming at the problem that there is still a certain deviation between the measured temperature and the actual temperature in the existing optical fiber temperature measurement device considering the fiber loss, after research, it is found that in order to realize the economy of optical fiber temperature measurement, an optical switch is often placed in the optical fiber temperature measurement device , realize time-sharing temperature measurement of multiple optical fiber lines

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