US 11,742,950 B2
Wavelength dispersion amount calculation apparatus and wavelength dispersion amount calculation method
Shimpei Shimizu, Musashino (JP); Takayuki Kobayashi, Musashino (JP); Masanori Nakamura, Musashino (JP); and Yutaka Miyamoto, Musashino (JP)
Assigned to NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
Appl. No. 17/777,569
Filed by NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
PCT Filed Nov. 28, 2019, PCT No. PCT/JP2019/046491
§ 371(c)(1), (2) Date May 17, 2022,
PCT Pub. No. WO2021/106126, PCT Pub. Date Jun. 3, 2021.
Prior Publication US 2022/0407600 A1, Dec. 22, 2022
Int. Cl. H04B 10/61 (2013.01); H04B 10/2513 (2013.01); H04B 10/079 (2013.01)
CPC H04B 10/2513 (2013.01) [H04B 10/07951 (2013.01); H04B 10/6161 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A chromatic dispersion amount calculation apparatus comprising:
a computation unit configured to use a difference between a signal power of an optical signal that is dispersion compensated with an assumed chromatic dispersion amount that is a chromatic dispersion amount assumed and a delayed signal power obtained by applying a delay to the signal power to compute an evaluation function for evaluating whether the assumed chromatic dispersion amount is a chromatic dispersion amount of the optical signal; and
a chromatic dispersion amount calculation unit configured to calculate the chromatic dispersion amount of the optical signal based on computation results of the evaluation function by the computation unit when a plurality of the assumed chromatic dispersion amounts that differ from each other are used,
wherein the computation unit includes
a dispersion compensation unit configured to perform dispersion compensation on a coherently received optical signal with the assumed chromatic dispersion amount,
a power arithmetic unit configured to perform arithmetic of the signal power of the optical signal that is dispersion compensated,
a delay applying unit configured to perform arithmetic of the delayed signal power obtained by applying a predetermined delay to the signal power,
a threshold determination unit configured to determine whether the signal power and the delayed signal power satisfy a threshold condition,
a computation availability determination unit configured to determine whether computation of the evaluation function is to be performed based on a determination of the threshold determination unit, and
an evaluation function computation unit configured to perform computation of the evaluation function by using the signal power and the delayed signal power when the computation availability determination unit determines that the computation is to be performed.