Patent ID: 7016023

Claim:
A method of measuring an optical property of a DUT, comprising: a) coupling a first pulse shaped optical signal having a first wavelength and a second pulse shaped optical signal having a second wavelength into the DUT, the second wavelength being variable with respect to the first wavelength, b) detecting the first and the second pulse shaped signals leaving the DUT, c) determining a difference in runtime, if any, between the first and the second pulse shaped signal having traveled at least one time through the DUT by measuring a relative group delay between the first and the second pulse shaped signal having traveled at least one time through the DUT using a single detector, and d) deriving the optical property from the detected difference and e) repeating steps a) to c) at least n times while varying the second wavelength with respect to the first wavelength before deriving the optical property from at least two of the detected differences, with n being a natural number.