Chirp measurement method, chirp measurement apparatus and their application

Abstract

A chirp measurement apparatus includes a splitting section for splitting input signal light to two paths; a first dispersion medium with a total dispersion amount of +D (≠0) at a used wavelength, and a second dispersion medium with a total dispersion amount of −D (≠0) at the used wavelength; first and second nonlinear photo-detecting sections for receiving the signal light beams passing through the first and second dispersion media, and for outputting electric signals with the intensities proportional to nth power of the intensities of the signal light beams, where n is greater than one; and a difference detecting section for computing a difference between the electric signals output from the first and second nonlinear photo-detecting sections, and for outputting a differential signal corresponding to the difference as a chirp signal of the input signal light.

1 - 9 . (canceled) 
   
   
       10 . A chirp measurement apparatus, comprising:
 splitting means for splitting input signal light to two paths;   a first dispersion medium with a total dispersion amount of +D (≠0) at a wavelength of the input signal light, and first nonlinear photo-detecting means for receiving the signal light passing through the first dispersion medium, and for outputting an electric signal with the intensity proportional to nth power of the intensity of the signal light, where n is greater than one, said first dispersion medium and said first nonlinear photo-detecting means being placed on a first path of the two paths;   a second dispersion medium with a total dispersion amount of −D (≠0) at the wavelength of the input signal light, and second nonlinear photo-detecting means for receiving the signal light passing through the second dispersion medium, and for outputting an electric signal with the intensity proportional to nth power of the intensity of the signal light, where n is greater than one, said second dispersion medium and said second nonlinear photo-detecting means being placed on a second path of the two paths;   difference detecting means for obtaining a difference between the electric signals output from said first nonlinear photo-detecting means and said second nonlinear photo-detecting means, and for outputting a differential signal corresponding to the difference as a chirp signal of the input signal light;   linear photo-detecting means for dividing part of the input signal light supplied to said splitting means, and for outputting an electric signal V 1  proportional to the optical intensity of the signal light; and   normalization means for normalizing the electric signal V 21  output from said first nonlinear photo-detecting means and the electric signal V 22  output from said second nonlinear photo-detecting means to electric signals V 21 /V 1   n  and V 22 /V 1   n  by the electric signal V 1 , and supplies the normalized electric signals to said difference detecting means.   
   
   
       11 . A chirp measurement apparatus, comprising:
 splitting means for splitting input signal light to two paths;   a first dispersion medium with a total dispersion amount of +D (≠0) at a wavelength of the input signal light, and first nonlinear photo-detecting means for receiving the signal light passing through the first dispersion medium, and for outputting an electric signal with the intensity proportional to nth power of the intensity of the signal light, where n is greater than one, said first dispersion medium and said first nonlinear photo-detecting means being placed on a first path of the two paths;   a second dispersion medium with a total dispersion amount of −D (≠0) at the wavelength of the input signal light, and second nonlinear photo-detecting means for receiving the signal light passing through the second dispersion medium, and for outputting an electric signal with the intensity proportional to nth power of the intensity of the signal light, where n is greater than one, said second dispersion medium and said second nonlinear photo-detecting means being placed on a second path of the two paths;   difference detecting means for obtaining a difference between the electric signals output from said first nonlinear photo-detecting means and said second nonlinear photo-detecting means, and for outputting a differential signal corresponding to the difference as a chirp signal of the input signal light;   in the two paths, a first linear photo-detecting means and a second photo-detecting means for dividing parts of the signal light supplied to said first and second nonlinear photo-detecting means, and for outputting electric signals V 11  and V 12  proportional to the optical intensity of the signal light, respectively; and   normalization means for normalizing the electric signals V 21  and V 22  output from said first and second nonlinear photo-detecting means into electric signals V 21 /V 11   n  and V 22 /V 12   n  by the electric signals V 11  and V 12 , and for supplying the normalized electric signals to said difference detecting means.   
   
   
       12 - 20 . (canceled)