MEASURING SYSTEM OF OFDR AND MEARSURING METHOD THEREOF

摘要

The present invention relates to a system for measuring optical frequency domain reflection, which comprises: a first optical coupler for dividing the light emitted from a wavelength variable laser through a first output end and a second output end to output the light; a sensing optical fiber connected to the first output end; a standard optical fiber connected to the second output end; a first light detector for detecting a first interference signal created by an interference between light reversely entered from the sensing optical fiber toward the first optical coupler and light reversely entered from the standard optical fiber toward the first optical coupler and output through a detecting end of the first optical coupler; a phase modulation signal generating unit for generating a second interference signal whose phase is converted by 90 degrees toward the first interference signal; and a calculation processing unit for respectively generating a first complex number signal, which has the first interference signal output through the detecting end of the first optical coupler as the real number unit and the second interference signal as the imaginary number unit, and a first conjugation complex number signal, which is a conjugation complex number for the first complex number signal to calculate the main value by subtracting a second Fourier transform value, which is obtained by performing the Fourier transform of the first conjugation complex number signal, from a first Fourier transform value, which is obtained by performing the Fourier transform for the first complex number signal, and to calculate the set physical quantity for the sensing optical fiber from the calculated main value. According to the system and measuring method of the present invention, a user can increase the length, which can be measured, of a sensing optical fiber since the user can process to be able to distinguish a peak in a frequency area with a positive direction where the length is increased, from a peak in a negative direction where the length is decreased, with the end of the standard optical fiber as the standard.