US 11,742,978 B2
Optical network device and method for monitoring transmission line
Kazuyuki Tajima, Yokosuka (JP); Takahito Tanimura, Yokohama (JP); Setsuo Yoshida, Inagi (JP); Eri Katayama, Fukuoka (JP); and Kiichi Sugitani, Fukuoka (JP)
Assigned to FUJITSU LIMITED, Kawasaki (JP)
Filed by FUJITSU LIMITED, Kawasaki (JP)
Filed on Dec. 17, 2021, as Appl. No. 17/554,096.
Claims priority of application No. 2020-216284 (JP), filed on Dec. 25, 2020; and application No. 2021-185433 (JP), filed on Nov. 15, 2021.
Prior Publication US 2022/0209884 A1, Jun. 30, 2022
Int. Cl. H04B 10/25 (2013.01); H04J 14/06 (2006.01); H04B 10/2513 (2013.01); H04B 10/2507 (2013.01)
CPC H04J 14/06 (2013.01) [H04B 10/2513 (2013.01); H04B 10/2572 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An optical network device comprising:
a receiver configured to receive a polarization multiplexed optical signal transmitted from a transmitter node; and
a processor configured to
separate an electric-field-information signal indicating an electric field of the polarization multiplexed optical signal into a first polarization component and a second polarization component orthogonal to each other,
generate a third polarization component and a fourth polarization component orthogonal to each other by controlling the first polarization component and the second polarization component in a coordinate system indicating a first polarization direction and a second polarization direction orthogonal to each other,
calculate an evaluation value corresponding to at least either a power of the third polarization component or a power of the fourth polarization component for each of a plurality of positions on an optical transmission line between the transmitter node and the optical network device,
calculate, for each of the plurality of positions, a variation in the evaluation value that is associated with a control amount in the controlling, and
decide whether a first position among the plurality of positions is a position to be detected based on a result of comparing a variation in an evaluation value calculated for the first position with a variation in an evaluation value calculated for a second position adjacent to the first position among the plurality of positions.