Apparatus and method for measuring the delay time difference between propagation modes

Abstract

The present disclosure relates to a device, including: a first light source for outputting incident light to a measured optical fiber or optical device; a second light source for outputting local light for being multiplexed with transmitted light through the measured optical fiber or optical device; and a signal processing unit for performing digital signal processing on a light-receiving signal I(t) obtained by multiplexing the transmitted light and the local light, wherein the signal processing unit is configured to calculate an autocorrelation function between the light-receiving signal I(t) and a signal I(t+τ) obtained by shifting the light-receiving signal by a time τ, and to measure a delay time difference between propagation modes in the measured optical fiber or optical device, from a peak position of the autocorrelation function.

Dependencies are inferred from the claim text.