Redundancy architectures and links
An optical link redundancy architecture includes an optical switch, an optical coupler, and an optical tap detector. The optical switch including a hub-side switch-port, a normal-mode switch-port, and a failover-mode switch-port. The optical coupler includes (i) a normal-mode coupler-port optically coupled to the normal-mode switch-port via a primary-path optical fiber, and (ii) a failover-mode coupler-port optically coupled to the failover-mode switch-port via a backup-path optical fiber. The optical tap detector (i) is optically coupled to the primary-path optical fiber, (ii) includes a monitor port communicatively coupled to the optical switch, and (iii) outputs a tap signal at the monitor port in response to an optical signal propagating in the primary-path optical fiber. The optical switch optically couples the hub-side switch-port to the failover-mode switch-port when the tap signal is less than a threshold value.
1. A redundancy link comprising:
a first optical switch including a switch-port A1 optically coupled to a multiplexed port M1 of a first network node, a switch-port A2 optically coupled to a demultiplexed port D2 of a second network node, and a switch-port A3 optically coupled to a multiplexed port M3 of a third network node via a first optical fiber; and
a second optical switch including a switch-port B1 optically coupled to a multiplexed port M2 of the second network node, a switch-port B2 optically coupled to a demultiplexed port D1 of the first network node, and a switch-port B3 optically coupled to a multiplexed port M4 of a fourth network node via a second optical fiber.
2. The redundancy link of claim 1 , further comprising a third optical fiber optically coupling the switch-port A2 to the demultiplexed port D2.
3. The redundancy link of claim 2 , further comprising a fourth optical fiber optically coupling the switch-port B2 to the demultiplexed port D1.
4. The redundancy link of claim 1 , further comprising a first optical circulator having (i) a first port optically coupled to the demultiplexed port D1, (ii) a second port, and (iii) a third port optically coupled to the switch-port A2.
5. The redundancy link of claim 4 , further comprising a second optical circulator having (i) a fourth port optically coupled to the demultiplexed port D2, (ii) a fifth port optically coupled to the second port of the first optical circulator, and (iii) a sixth port optically coupled to the switch-port B2.
6. An optical network comprising: the redundancy link of claim 1 , the first network node, and the second network node.
7. The optical network of claim 6 , further comprising:
a third optical fiber optically coupling the switch-port A2 to the demultiplexed port D2;
wherein the second network node includes one of (i) a demultiplexer and (ii) a wavelength-selective switch, multiplexed port M2 and demultiplexed port D2 being respective ports thereof.
8. The optical network of claim 7 , further comprising:
a fourth optical fiber optically coupling the switch-port B2 to the demultiplexed port D1;
wherein the first network node includes one of (i) a demultiplexer and (ii) a wavelength-selective switch, multiplexed port M1 and demultiplexed port D1 being respective ports thereof.
9. The optical network of claim 8 , further comprising:
the third network node;
the fourth network node, a first distance between the first and the second network nodes being less than a second distance between the third and the fourth network nodes;
a transceiver T 3 optically coupled to the switch-port A3 via the third network node and the first optical fiber; and
a protection transceiver P 4 communicatively coupled to the transceiver T 3 and optically coupled to the switch-port B3 via the fourth network node and the second optical fiber.
10. The optical network of claim 8 , further comprising:
a transceiver T 4 optically coupled to the switch-port B3 via the fourth network node and the second optical fiber; and
a protection transceiver P 3 communicatively coupled to the transceiver T 4 and optically coupled to the switch-port A3 via the third network node and the first optical fiber.
11. The optical network of claim 7 , further comprising:
a first optical tap detector that (i) is optically coupled to the first optical fiber, (ii) includes a first monitor port communicatively coupled to the first optical switch, and (iii) outputs a first tap signal to the first monitor port in response to a first optical signal propagating in the first optical fiber; and
a second optical tap detector that (i) is optically coupled to the second optical fiber, (ii) includes a second monitor port communicatively coupled to the second optical switch, and (iii) outputs a second tap signal to the second monitor port in response to a first optical signal propagating in the second optical fiber;
the first optical switch being configured to optically couple the switch-port A2 to the switch-port A1 when the first tap signal is less than a first threshold value;
the second optical switch being configured to optically couple the switch-port B2 to the switch-port B1 when the second tap signal is less than a second threshold value.