| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize a measuring/detecting method using a distribution type sensor, e.g. Bragg's lattice, by delivering an optical signal having a wavelength close to that at the center of reflection to one end of an optical fiber and comparing a reflection output, detected as a function of time, with a reflection output under a state having no variation in the physical quantity. SOLUTION: A fiber 1 has a silica based optical core incorporating a Bragg's lattice 4 having substantially identical reflection wavelength. The lattice 4 is constituted of a continuation of periodic variation in the refractive index of core of the fiber 1. When a temperature variation is detected using a sensor. 100, for example, an optical pulse 7 is delivered from a light source 5 through a coupler 6 to the fiber 1. Wavelength of the optical pulse 7 is selected substantially equal to the wavelength at the center of reflection. When a temperature variation occurs at any level of the lattice 4, the reflection pulse from the varied lattice 4 has an amplitude different from that of other pulse. The reflected output is received by a receiver 8 through a coupler 6 and detected visually through a visualization means 9.</p> |
