Patent ID: 6958467

Claim:
A chirp measurement apparatus comprising: a dispersion medium with a total dispersion amount of +D (≠0) at the wavelength of an input signal light; linear photo-detecting means for receiving a divided part of the signal light passing through said dispersion medium, and for outputting an electric signal V 1 with intensity proportional to the optical intensity of the received part of the divided signal light; nonlinear photo-detecting means for receiving the other part of divided input signal light for outputting an electric signal V 2 with intensity proportional to nth power of the optical intensity of the received other part of divided input signal light; and normalization means for normalizing the electric signal V 2 output from said nonlinear photo-detecting means to an electric signal V 2 /V 1 n by the electric signal V 1 , and for outputting the electric signal V 2 /V 1 n as a chirp signal of the input signal light.