US 11,658,750 B2
Submarine optical communication system and submarine branching apparatus
Ryuji Aida, Tokyo (JP); and Eduardo Mateo Rodriguez, Tokyo (JP)
Assigned to NEC CORPORATION, Tokyo (JP)
Appl. No. 16/756,200
Filed by NEC Corporation, Tokyo (JP)
PCT Filed Aug. 15, 2018, PCT No. PCT/JP2018/030333
§ 371(c)(1), (2) Date Apr. 15, 2020,
PCT Pub. No. WO2019/087520, PCT Pub. Date May 9, 2019.
Claims priority of application No. JP2017-208874 (JP), filed on Oct. 30, 2017.
Prior Publication US 2021/0194597 A1, Jun. 24, 2021
Int. Cl. H04B 10/00 (2013.01); H04B 10/80 (2013.01); H04B 10/25 (2013.01); H04Q 11/00 (2006.01)
CPC H04B 10/80 (2013.01) [H04B 10/25 (2013.01); H04Q 11/0005 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A submarine optical communication system comprising:
a first optical transmission apparatus outputting a first optical signal;
a second optical transmission apparatus;
a third optical transmission apparatus outputting a monitoring signal;
a submarine branching apparatus including a first filter unit returning the monitoring signal received from the third optical transmission apparatus and switching an output destination of the first optical signal received from the first optical transmission apparatus to the second optical transmission apparatus or the third optical transmission apparatus;
a first optical fiber transmitting the first optical signal output from the submarine branching apparatus to the third optical transmission apparatus; and
a second optical fiber connecting the third optical transmission apparatus and the submarine branching apparatus, wherein
the submarine branching apparatus comprises:
a first optical switch receiving the first optical signal from the first optical transmission apparatus;
a second optical switch outputting an optical signal input thereto to the second optical transmission apparatus; and
a control unit controlling the first and second optical switches in accordance with an instruction from the first optical transmission apparatus, wherein
the third optical transmission apparatus comprises:
an optical transmission/reception unit outputting the monitoring signal to one end of the second optical fiber;
a detection unit detecting the monitoring signal which is returned from the first filter unit, transmitted through the first optical fiber, and input to the third optical transmission apparatus;
a notification unit notifying the first optical transmission apparatus of a result of the detection by the detection unit; and
a second filter unit outputting an optical signal having a prescribed wavelength contained in the first optical signal received from the submarine branching apparatus to the optical transmission/reception unit via the first optical fiber and returning an optical signal having another wavelength contained in the first optical signal received from the submarine branching apparatus to the submarine branching apparatus via the second optical fiber, wherein
under a state in which the output destination of the first optical signal is the third optical transmission apparatus, the third optical transmission apparatus detects the monitoring signal returned from the first filter unit, and notifies the first optical transmission apparatus of the result of the detection when the optical intensity of the monitoring signal received by the third optical transmission apparatus is smaller than the prescribed value, and
the first optical transmission apparatus instructs the submarine branching apparatus to switch the output destination of the first optical signal to the second optical transmission apparatus in accordance with the notification, and
when receiving the instruction, the control unit:
 switches an output destination of the first optical signal of the first optical switch from the third optical transmission apparatus to the second optical switch, and
 switches an input source of the optical signal input to the second optical switch from the third optical transmission apparatus to the first optical switch.