Patent ID: 9197950
Filing Date: 2015-11-24
Classification: G02B,H04J,H04Q

Abstract:
1. An optical branching/synthesizing device for use in an optical distribution network in which optical communication is performed between an OLT device on a base station side and a plurality of ONU devices on a subscriber side, the optical branching/synthesizing device comprising: a first-stage optical branching coupler that is an optical branching coupler including a pair of first light input/output ends and a pair of second light input/output ends, branching light input from one of the pair of first light input/output ends to the pair of second light input/output ends, and branching light input from one of the pair of second light input/output ends to the pair of first light input/output ends, and receives a downstream optical signal having a first wavelength at one of the pair of first light input/output ends from the OLT device; a final-stage optical branching coupler that is an optical branching coupler including a pair of third light input/output ends and a pair of fourth light input/output ends, branching light input from one of the pair of third light input/output ends to the pair of fourth light input/output ends, and branching light input from one of the pair of fourth light input/output ends to the pair of third light input/output ends, in which the pair of fourth light input/output ends transmits the downstream signal to each ONU device and receives an upstream optical signal having a second wavelength from each ONU device; an optical combiner that combines the upstream optical signals output from the other of the pair of first light input/output ends of the first-stage optical branching coupler and from the other of the pair of third light input/output ends of the final-stage optical branching coupler; and an intermediate-stage optical branching coupler that is an optical branching coupler including a pair of sixth light input/output a pair of seventh light input/output ends, branching light input from one of the pair of sixth light input/output ends to the pair of seventh light input/output ends, and branching light input from one of the pair of seventh light input/output ends to the pair of sixth light input/output ends, in which one of the pair of sixth light input/output ends is optically coupled to one of the second light input/output ends of the first-stage optical branching coupler, and one of the pair of seventh light input/output ends is optically coupled to one of the pair of third light input/output ends of the final-stage optical branching coupler, wherein the optical combiner further combines the upstream optical signal output from the other of the pair of sixth light input/output ends of the intermediate-stage optical branching coupler.