OPTICAL POWER DISTRIBUTION ESTIMATION APPARATUS, OPTICAL POWER DISTRIBUTION ESTIMATION METHOD, AND COMPUTER PROGRAM
An optical power distribution estimation device includes: a partial wavelength dispersion application unit that applies, to a signal, partial wavelength dispersion corresponding to a distance from an optical transmission device to an optical power measurement position; a nonlinear operation unit that performs, on the signal to which the partial wavelength dispersion has been applied, nonlinear operation using a linear term obtained by Taylor-expanding a mathematical expression used for phase rotation; a residual dispersion application unit that applies residual wavelength dispersion corresponding to a distance from the optical power measurement position to an optical reception device to the signal subjected to the nonlinear operation by the nonlinear operation unit; and a correlation calculation unit that estimates an optical power distribution of an optical transmission line by obtaining, for each optical power measurement position, a correlation between the signal to which the residual wavelength dispersion has been applied and a reception signal based on an optical signal transmitted from the optical transmission device and received via the optical transmission line.
1 . An optical power distribution estimation device comprising:
a partial wavelength dispersion applicator configured to apply, to a signal, partial wavelength dispersion corresponding to a distance from an optical transmission device to an optical power measurement position;
a nonlinear operator configured to perform, on the signal to which the partial wavelength dispersion has been applied, nonlinear operation using a linear term obtained by Taylor-expanding a mathematical expression used for phase rotation;
a residual dispersion applicator configured to apply residual wavelength dispersion corresponding to a distance from the optical power measurement position to an optical reception device to the signal subjected to the nonlinear operation by the nonlinear operator; and
a correlation calculator configured to estimate an optical power distribution of an optical transmission line by obtaining, for each optical power measurement position, a correlation between the signal to which the residual wavelength dispersion has been applied and a reception signal based on an optical signal transmitted from the optical transmission device and received via the optical transmission line.
2 . The optical power distribution estimation device according to claim 1 , further comprising
a transmission signal restore configured to restore a transmission signal transmitted by the optical transmission device on a basis of the reception signal, wherein
the partial wavelength dispersion applicator applies the partial wavelength dispersion to the restored transmission signal or a signal obtained by performing predetermined processing on the restored transmission signal.
3 . The optical power distribution estimation device according to claim 2 , further comprising
a preprocessor configured to perform the predetermined processing on the transmission signal restored by the transmission signal restorer, wherein:
the reception signal is a signal in which an influence caused by the optical transmission line has not been compensated for;
the transmission signal restorer restores the transmission signal on a basis of a signal in which the influence caused by the optical transmission line has been compensated for; and
as the predetermined processing, the preprocessor applies a value corresponding to the influence caused by the optical transmission line in order to bring the transmission signal close to the reception signal.
4 . The optical power distribution estimation device according to claim 2 , wherein:
the reception signal is a signal in which an influence caused by the optical transmission line has been compensated for;
the transmission signal restorer restores the transmission signal on a basis of the signal in which the influence caused by the optical transmission line has been compensated for; and
the partial wavelength dispersion applicator applies the partial wavelength dispersion to the restored transmission signal.
5 . An optical power distribution estimation method comprising:
applying, to a signal, partial wavelength dispersion corresponding to a distance from an optical transmission device to an optical power measurement position;
performing, on the signal to which the partial wavelength dispersion has been applied, nonlinear operation using a linear term obtained by Taylor-expanding a mathematical expression used for phase rotation;
applying residual wavelength dispersion corresponding to a distance from the optical power measurement position to an optical reception device to the signal subjected to the nonlinear operation; and
estimating an optical power distribution of an optical transmission line by obtaining, for each optical power measurement position, a correlation between the signal to which the residual wavelength dispersion has been applied and a reception signal based on an optical signal transmitted from the optical transmission device and received via the optical transmission line.
6 . A non-transitory storage medium that stores a program for making a computer perform processes, the processes comprising:
applying, to a signal, partial wavelength dispersion corresponding to a distance from an optical transmission device to an optical power measurement position;
performing, on the signal to which the partial wavelength dispersion has been applied, nonlinear operation using a linear term obtained by Taylor-expanding a mathematical expression used for phase rotation;
applying residual wavelength dispersion corresponding to a distance from the optical power measurement position to an optical reception device to the signal subjected to the nonlinear operation; and
estimating an optical power distribution of an optical transmission line by obtaining, for each optical power measurement position, a correlation between the signal to which the residual wavelength dispersion has been applied and a reception signal based on an optical signal transmitted from the optical transmission device and received via the optical transmission line.