Optical fiber test method and optical fiber test equipment

Abstract

An object is to provide an optical fiber test method and an optical fiber test device capable of acquiring a maximum loss of a higher-order mode at a connection point of an optical fiber transmission line through which a plurality of modes propagate. The optical fiber test device according to the present invention includes: a light source unitthat allows probe light L, which has a tunable wavelength and is continuous light, to enter one end Tof an optical fiber in a fundamental mode and allows pulsed pump light L, which is shifted to a high frequency side by a frequency at which a Brillouin interaction occurs with respect to the probe light L, to enter the other end Tof the optical fiber in a higher-order mode as a measurement target; and an analysis unitthat acquires, from a light intensity of the probe light Lamplified by the pump light L, a time waveform of an amplification component, calculates a connection loss of the pump light Lat a connection point from a ratio of the amplification components before and after the connection point, acquires a wavelength dependency of the connection loss, detects a maximum value of the connection loss from the wavelength dependency of the connection loss, and sets the maximum value as a maximum loss of the higher-order mode at the connection point.