Four fiber ring network optical switching circuit using branched inputs

• US 20020075535A1
• Filed: 12/07/2000
• Published: 06/20/2002
• Est. Priority Date: 12/08/1999
• Status: Active Grant

• Current Assignee: KDD Submarine Cable Systems Inc., DDI Corporation (TTM Technologies Incorporated)
• Original Assignee: KDD Submarine Cable Systems Inc., DDI Corporation (TTM Technologies Incorporated)
• Inventors: Otani, Tomohiro, Yamamoto, Shu, Nagao, Yasuyuki, Miyazaki, Tetsuya
• Granted Patent: US 6,782,201 B2
• Time in Patent Office: Days
• US Class Current: 398/3
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0291 Shared protection at the optical multiplex section (1:1, n:m)
• CPC Class Codes: H04Q 2011/0058 Crossbar; Matrix
• CPC Class Codes: H04Q 2011/0081 Fault tolerance; Redundancy; Recovery; Reconfigurability

Abstract

A four fiber ring network optical switching circuit capable of realizing the bridge function at times of the span switching and the ring switching economically by a very compact structure is disclosed. A four fiber ring network optical switching circuit is formed by a 10×8 optical matrix switch having ten input ports and eight output ports, and two branching elements adapted to branch each one of two optical signals among eight optical signals that are inputs of the four fiber ring network optical switching circuit, into two identical optical signals, and to enter the two identical optical signals into two input ports of the 10×8 optical matrix switch such that the eight optical signals are entered into the ten input ports of the 10×8 optical matrix switch as ten optical signals.

Claims

1. A four fiber ring network optical switching circuit, comprising:

a 10×

8 optical matrix switch having ten input ports and eight output ports; and

two branching elements adapted to branch each one of two optical signals among eight optical signals that are inputs of the four fiber ring network optical switching circuit, into two identical optical signals, and to enter the two identical optical signals into two input ports of the 10×

8 optical matrix switch such that the eight optical signals are entered into the ten input ports of the 10×

8 optical matrix switch as ten optical signals.

2. The four fiber ring network optical switching circuit of claim 1, wherein a combination of the 10×

8 optical matrix switch and the two branching elements is provided in plural sets, such that the plural sets of the combination of the 10×

8 optical matrix switch and the two branching elements carry out switching of a plurality of four fiber rings.

3. A four fiber ring network optical switching circuit to be used at nodes for connecting optical fiber transmission paths in a ring shape so as to form a bidirectional optical ring network, the four fiber ring network optical switching circuit comprising:

first and second working and protection input and output ports and first and second working and protection add/drop input and output ports adapted to input and output working and protection signals to be transmitted through the bidirectional optical ring network;

first and second branching elements adapted to branch each one of optical input signals for the first and second working add/drop input ports, and having first and second working add/drop branch-1 and branch-2 input ports for outputting branched optical signals; and

an optical matrix switch adapted to cross-connect a plurality of input ports including the first and second working and protection input ports, the first and second protection add/drop input ports and the first and second working add/drop branch-1 and branch-2 input ports, and a plurality of output ports including the first and second working and protection output ports and the first and second working and protection add/drop output ports, so as to realize a span switching function and a ring switching function.

4. The four fiber ring network optical switching circuit of claim 3, wherein the plurality of input ports includes at least ten input ports, the plurality of output ports includes eight output ports, and the optical matrix switch is a 10×

8 optical matrix switch.

5. The four fiber ring network optical switching circuit of claim 4, wherein a combination of the 10×

8 optical matrix switch and the two branching elements is provided in plural sets, such that the plural sets of the combination of the 10×

8 optical matrix switch and the two branching elements carry out switching of a plurality of four fiber rings.

6. The four fiber ring network optical switching circuit of claim 3, further comprising:

third and fourth branching elements adapted to branch each one of optical input signals for the first and second protection add/drop input ports, and having first and second protection add/drop branch-1 and branch-2 input ports for outputting branched optical signals;

wherein the optical matrix switch is a 12×

8 optical matrix switch in which working ports and protection ports are formed symmetrically such that functions of a working ring and a protection ring are reversible.

7. The four fiber ring network optical switching circuit of claim 3, wherein the optical matrix switch is a 10m×

8m optical matrix switch, where m is an integer, such that the 10m×

8m optical matrix switch carries out switching of m sets of four fiber rings, by being connected over rings including individual working and protection rings of m sets of the four fiber rings