SYSTEM AND METHOD FOR MEASURING CHROMATIC DISPERSION

摘要

PURPOSE: A system and a method for measuring chromatic dispersion are provided to measure chromatic dispersion with accurate solution, and easily measure chromatic dispersion of an optical fiber already installed in the field. CONSTITUTION: A system for measuring chromatic dispersion includes a tunable laser source(10) which is a light source for measuring chromatic dispersion; an optical fiber 3dB coupler(30) dividing a path of light provided from the wavelength variable laser through a circulator(20), and coupling predetermined optical signals; an MZ(Mach Zehnder) modulator(40) backward and forward modulating light provided being divided into clockwise direction and counterclockwise direction through the optical fiber 3dB coupler by an RF signal provided from the outside; a Sagnac interferometer having a fiber under test(FUT) inserted into clockwise path between the optical fiber 3dB coupler and the MZ modulator for modulating light by the delayed signal as much as the corresponding length in case of forward modulation of the MZ modulator; a photo detector(50) receiving the backward and forward modulated light through the optical fiber 3dB coupler and the circulator; a circuit network analyser(60) providing the RF signal to the MZ modulator and obtaining a transfer function of the signal received in the photo detector; and a computer(70) calculating a delayed time corresponding to asymmetrical length of the FUT by using the obtained transfer function, thereby obtaining chromatic dispersion.