BRANCHED OPTICAL LINE CHARACTERISTIC ANALYSIS SYSTEM, BRANCHED OPTICAL LINE, AND MANUFACTURING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To maintain measurement accuracy while reducing measurement intervals and speed up measurement when executing the measurement of a branched optical line repeatedly a number of times.;SOLUTION: In a branched optical fiber sensor head 2, a difference in the amount of a Brillouin frequency shift (BFS) between a branched upper optical fiber F₀ and branched lower optical fibers F₁ -F_N is set to be larger than a Brillouin gain bandwidth. The pulse width τ_probe of a probe light pulse is set to be smaller than the minimum value of the time difference 2nΔL/c of return light from the branched lower optical fibers F₁ -F_N, where ΔL represents the minimum value of a difference in length between the branched lower optical fibers F₁ -F_N, c represents high speed in a vacuum, and n represents the refractive index of a second optical fiber. Furthermore, the operation bandwidths of an optical receiver 23 and an A/D converter 24 are set to be wider than a bandwidth in which the pulse width τ_probe of the probe light pulse can be received.;COPYRIGHT: (C)2016,JPO&INPIT