Patent ID: 8724117
Filing Date: 2014-05-13
Classification: G01N

Abstract:
1. A method of measuring an electro-optic coefficient by using interference fringe measurement, wherein the method is performed by using a system for measuring an electro-optic coefficient by using interference fringe measurement, the system comprising: a light source for outputting an optical beam of multi-wavelengths; an optical interferometer comprising: an optical spectrum analyzing device for receiving the mutually interfered optical beam from the optical interferometer and analyzing a spectrum of the mutually interfered optical beam, wherein the optical beam splitter and the optical beam combiner are separate from each other, the method comprising: obtaining a reference frequency spectrum by measuring a spectrum of the beam penetrated through and output from the interferometer while no voltage is applied to the optical sample, and converting the wavelength to corresponding frequency; obtaining a reference interference fringe spectrum by normalizing the obtained reference frequency spectrum by excluding the spectral intensity distribution values of the optical beam calculated with a Hilbert transform from the obtained reference frequency spectrum; calculating reference phase difference values as a function of frequency change from a predetermined reference frequency, by using the obtained reference interference fringe spectrum; obtaining a voltage-on frequency spectrum by measuring a spectrum penetrated through and output from the optical interferometer while a voltage is applied to the optical sample, and converting the wavelength to a frequency; obtaining a voltage-on interference fringe spectrum by normalizing the optical beam intensity distribution calculation value according to Hilbert transform excluding from the obtained voltage-on frequency spectrum; calculating voltage-on phase difference values as a function of frequency change from the predetermined reference frequency, by using the obtained voltage-on interference fringe spectrum; determining fitting functions for each of the reference phase difference values and the voltage-on phase difference values by data-fitting the reference phase difference values and the voltage-on phase difference values; and calculating an electro-optic coefficient value by obtaining a reference phase difference value (φ(f