| 摘要 |
<p>PURPOSE:To simplify the mechanism along with a higher accuracy in the temperature measurement by using a double refractive optical fiber as sensor while the phase of a signal based on the change in the double refraction property due to temperature is detected in a digital manner. CONSTITUTION:A thermometer is composed of a light source 1 of semiconductor laser, a linear polarizer 2, a double refractive optical fiber 3, a light beam splitter 4, a 1/4 wavelength plate 5, polarizers 6 and 8, a photodetectors 7 and 9 and a counter 10. As leaving the other end of an optical fiber 3 propagating therethrough, light from the light source 1 is divided into two with the splitter 4. One beam is shifted by 90 deg. in the phase difference passing through a 1/4 wavelength plate 5 and gives a signal of light intensity I1 received with the detector 7. The other beam passes through the polarizer 8 and gives an electrical signal of light intensity I2 received with the detector 9. Then, the counter 10 counts the light intensities I1 and I2 to calculate the temperature of the optical fiber 3 from the counts.</p> |
