TEMPERATURE SENSOR

Abstract

A temperature sensor includes: a light source outputting test light; a sensor optical fiber transmitting, when the test light is inputted, the test light at any temperature within a temperature range of 20° C. to 150° C. with a loss of 0.3 dB/m or more; a light receiver receiving the test light transmitted by the sensor optical fiber; and a processing device detecting temperature of the sensor optical fiber based on intensity of the test light received by the light receiver. The sensor optical fiber includes a core, and a clad provided on an outer circumference of the core; and, when the temperature of the sensor optical fiber increases, the temperature sensor 1 detects the temperature with a change in the intensity of the test light received by the light receiver increases, caused by an increase in a refractive index difference between the core and the clad, and an increase in confinement of the test light transmitted in the core.

Description

Claims

1. A temperature sensor comprising: a light source outputting test light;a sensor optical fiber transmitting, when the test light is inputted, the test light at any temperature within a temperature range of 20° C. to 150° C. with a loss of 0.3 dB/m or more;a light receiver receiving the test light transmitted by the sensor optical fiber; anda detection unit detecting temperature of the sensor optical fiber based on intensity of the test light received by the light receiver; wherein the sensor optical fiber comprises a core, and a clad provided on an outer circumference of the core; andwhen the temperature of the sensor optical fiber increases, the detection unit detects the temperature with a change in the intensity of the test light received by the light receiver, caused by an increase in a refractive index difference between the core and the clad, and an increase in confinement of the test light transmitted in the core.

2. The temperature sensor according to claim 1, wherein, in the sensor optical fiber, a diameter of the core is equal to or more than ten times a thickness of the clad.

3. The temperature sensor according to claim 2, wherein in the sensor optical fiber, a plurality of nanostructures exist near an interface between the core and the clad; anda cross-sectional diameter of a cross section of each of the nanostructures is 100 nm or less, the cross section being perpendicular to a longitudinal direction of the sensor optical fiber, and the nanostructures are distributed in areas in the longitudinal direction, each of the areas having a length below 1 m.

4. The temperature sensor according to claim 3, wherein the sensor optical fiber transmits the test light with a light output change rate of 0.008 µW/°C or higher within the temperature range of 20° C. to 150° C.