Patent ID: 11888583
Assignee: NEC CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 0:
1. A 3 way branching unit switch module for undersea optical communications configured to be connected to first, second, and third optical cables, each of the optical cables in optical communication with a respective landing station A, B, or C, the module comprising:
six switches configured as:
a first pair of switches in optical communication with the first optical cable;
a second pair of switches in optical communication with the second optical cable; and
a third pair of switches in optical communications with the third optical cable;, wherein the first, second and third pair of switches each have one switch of their pair in optical communication with one of the other two pair of switches and the first, second and third pair of switches each have the other switch in their pair in optical communication with the other one of the other two pair of switches;, wherein each switch includes a circulator optically connecting a respective optical fiber of the optical cable to a respective port;, wherein the landing stations are configured to provide one state of connectivity to the landing stations
A, B, and C selected from the group consisting of:
a first state of connectivity consisting of one connection between landing stations A and B, and one connection between landing stations A and C, and one connection between landing stations B and C;
a second state of connectivity consisting of two connections between landing stations A and B, and no connections between landing stations A and C, and no connections between landing stations B and C;
a third state of connectivity consisting of no connections between landing stations A and B, and two connections between landing stations A and C, and no connections between landing stations B and C; and
a fourth state of connectivity consisting of no connections between landing stations A and B, and no connection between landing stations A and C, and two connections between landing stations B and C.