Optical fiber temperature sensor
The present invention relates to an optical fiber temperature sensor capable of reducing an error in a temperature measurement. The sensor comprises an optical fiber, an optical frequency difference adjusting section, a light source system, a spectrum measuring section, a temperature calculating section, and a correcting section. The light source system outputs, into different ends of the optical fiber, probe light and pumping light of which each center frequency is set corresponding to an instruction from the optical frequency difference indicating section respectively. The temperature calculating section calculates a temperature of an object based on BGS in a first domain measured by the spectrum measuring section. On the other hand, the correcting section outputs a correction instruction to the light source system so that BGS center frequency of a second domain may be in agreement with a reference value thereof.
1. An optical fiber temperature sensor, comprising:
an optical fiber including a first domain installed in an object, and a second domain set as a specified temperature;
an optical frequency difference adjusting section for sweeping a difference between each center frequency of probe light and pumping light to be inputted into the optical fiber;
a light source system for outputting the probe light into one end of the optical fiber, while outputting the pumping light into the other end of the optical fiber, each center frequency of the probe light and the pumping light being set by an indication of the optical frequency difference adjusting section;
a spectrum measuring section for receiving, as an outputted light from the optical fiber, the probe light having acquired a gain by Brillouin scattering generated with propagation of the probe light and the pumping light from the light source system, and for measuring data relevant to a shape of a Brillouin gain spectrum, the Brillouin gain spectrum being the spectrum of the gain acquired by the received probe light by the Brillouin scattering;
a temperature calculating section for computing a temperature distribution of the first domain in the optical fiber based on a measurement data relevant to the shape of the Brillouin gain spectrum of the first domain measured by the spectrum measuring section; and
a correcting section for instructing correction of at least one of optical frequencies of the pumping light and the probe light outputted to the optical fiber to the light source system so as to make known reference data relevant to the shape of the Brillouin gain spectrum set up in advance as the reference value of the Brillouin gain spectrum of the second domain at the specified temperature be in agreement with the measurement data relevant to the shape of the Brillouin gain spectrum of the second domain.
2. An optical fiber temperature sensor, comprising:
an optical fiber including a first domain installed in an object, and a second domain set as a specified temperature;
a light source system for outputting probe light to one end of the optical fiber, while outputting pumping light to the other end of the optical fiber;
a spectrum measuring section for receiving, as an outputted light from the optical fiber, the probe light having acquired a gain by Brillouin scattering generated with propagation of the probe light and the pumping light from the light source system, and for measuring data relevant to a shape of a Brillouin gain spectrum, the Brillouin gain spectrum being the spectrum of the gain acquired by the received probe light by the Brillouin scattering;
a correcting section for outputting an optimum value as a correction value among values set up in advance as a reduced value of an amount of a temperature correction corresponding to a difference between a reference data and a measurement data, based on the difference between known reference data relevant to the shape of the Brillouin gain spectrum set up in advance as the reference value of the Brillouin gain spectrum of the second domain at the specified temperature and a measurement data relevant to the shape of the Brillouin gain spectrum of the second domain; and
a temperature calculating section for computing a corrected temperature distribution in the first domain in the optical fiber based on the measurement data relevant to the shape of the Brillouin gain spectrum of the first domain measured by the spectrum measuring section and the correction value outputted from the correcting section.
3. An optical fiber temperature sensor, comprising:
an optical fiber including a first domain installed in an object, and a second domain to be temperature-measured by a specified temperature measuring means;
an optical frequency difference adjusting section for sweeping a difference between each center frequency of probe light and pumping light to be inputted into the optical fiber;
a light source system for outputting the probe light into one end of the optical fiber, while outputting the pumping light into the other end of the optical fiber, each center frequency of the probe light and the pumping light being set by a instruction of the optical frequency difference adjusting section;
a spectrum measuring section for receiving, as an outputted light from the optical fiber, the probe light having acquired a gain by Brillouin scattering generated with propagation of the probe light and the pumping light from the light source system, and for measuring data relevant to a shape of the Brillouin gain spectrum, the Brillouin gain spectrum being the spectrum of the gain acquired by the received probe light by the Brillouin scattering;
a temperature calculating section for computing a temperature distribution of the first domain in the optical fiber based on a measurement data relevant to the shape of the Brillouin gain spectrum of the first domain measured by the spectrum measuring section;
a storage section for storing known reference data relevant to the shape of the Brillouin gain spectrum set up in advance as reference values of the Brillouin gain spectrum of the second domain with respect to various temperatures; and
a correcting section for instructing correction of at least one of optical frequencies of the pumping light and the probe light outputted to the optical fiber to the light source system so as to make the measurement data relevant to the shape of the Brillouin gain spectrum of the second domain be in agreement with the reference data corresponding to the temperature of the second domain measured by the temperature measuring means among the reference data stored in the storage part.
4. An optical fiber temperature sensor, comprising:
an optical fiber including a first domain installed in an object, and a second domain to be temperature-measured by a specified temperature measuring means;
a light source system for outputting probe light to one end of the optical fiber, while outputting pumping light to the other end of the optical fiber;
a spectrum measuring section for receiving, as an outputted light from the optical fiber, the probe light having acquired a gain by Brillouin scattering generated with propagation of the probe light and the pumping light from the light source system, and for measuring data relevant to a shape of the Brillouin gain spectrum, the Brillouin gain spectrum being the spectrum of the gain acquired by the received probe light by the Brillouin scattering;
a storage section for storing known reference data relevant to the shape of the Brillouin gain spectrum set up in advance as reference values of the Brillouin gain spectrum of the second domain with respect to various temperatures;
a correcting section for outputting an optimum value as a correction value among values set up in advance as a reduced value of an amount of a temperature correction corresponding to a difference of a reference data and a measurement data based on the difference between the reference data corresponding to the temperature of the second domain measured by the specified temperature measuring means among the reference data stored in the storage part and a measurement data relevant to the shape of the Brillouin gain spectrum of the second domain; and
a temperature calculating section for computing a corrected temperature distribution in the first domain in the optical fiber based on the measurement data relevant to the shape of the Brillouin gain spectrum of the first domain measured by the spectrum measuring section and the correction value outputted from the correcting section.