Protection switching arrangement for an optical switching system
View Patent ↗A protection arrangement for an optical switching system includes protection switching for switch planes in the optical core and for ports in the tributary cards. For a multiple layer switch core protection is also provided between layers. A first layer is for switching optical channels. The protection switches used may be 1×N, 2×N or 3×N MEMS optical switches. The 1×N MEMS provides for protection switching. The 2×N MEMS provides protection switching and testing capability. The 3×N MEMS provides for protection switching, testing and backup of the protection switching. Application of these protection switches is shown in lambda plane switch cores, multiple layer switch cores and combined switch cores.
1. A protection switching arrangement comprising:
a first layer for switching a plurality of optical channel signals;
a second layer, coupled to said first layer, for switching a plurality of optical channel signal groups, each optical channel signal group including at least one of said optical channel signals, said second layer comprising:
a plurality of optical channel group switches, each including a plurality of input ports; and
a protection optical channel group switch including a plurality of input ports;
an optical protection switch, coupled to said second layer, for providing in said second layer an alternative switch path for each of said optical channel signal groups, said optical protection switch including a plurality of output ports and a protection output port, each output port of said optical protection switch being coupled to a respective input port of a respective one of the optical channel group switches, said protection output port of said optical protection switch being coupled to one of said input ports of said protection optical channel group switch so as to provide said alternative switch path.
2. A protection switching arrangement as claimed in claim 1 , further comprising a demultiplexer including:
an input port for receiving a composite optical signal; and
a plurality of output ports for each releasing a respective one of said optical channel signal groups;
wherein said optical protection switch includes a plurality of input ports, each of said input ports of said optical protection switch being coupled to a respective one of said output ports of said demultiplexer.
3. A protection switching arrangement as claimed in claim 1 , further comprising a plurality of multiplexers each including:
a respective plurality of input ports for each receiving a respective one of said optical channel signals; and
a respective output port for releasing a respective one of said optical channel signal groups;
wherein said optical protection switch includes a plurality of input ports, each of said input ports of said optical protection switch being coupled to the respective output port of each multiplexer.
4. A protection switching arrangement as claimed in claim 3 , wherein said optical protection switch is a first optical protection switch, said protection switching arrangement further comprising a second optical protection switch, coupled to said first layer, for providing in said first layer an alternative switch path for each of said optical channel signals, said first layer comprising:
a plurality of optical channel switches, each including a plurality of output ports; and
a protection optical channel switch including a plurality of output ports;
said second optical protection switch including a plurality of input ports and a protection input port, each of said input ports of said second optical protection switch being coupled to a respective one of said output ports of a respective one of said optical channel switches, said protection input port of said second optical protection switch being coupled to a respective one of said output ports of said protection optical channel switch so as to provide in said first layer said alternative switch path for each of said optical channel signals, said second optical protection switch including a plurality of output ports, each of said output ports of said second optical protection switch being coupled to a respective one of said input ports of a respective one of said multiplexers.
5. A protection switching arrangement as claimed in claim 1 , wherein:
said optical protection switch is a first optical protection switch;
each of said optical channel group switches includes a respective plurality of output ports; and
said protection optical channel group switch includes a plurality of output ports;
said protection switching arrangement further comprising a second optical protection switch coupled to said second layer, said second optical protection switch including a plurality of input ports and a protection input port, each of said input ports of said second optical protection switch being coupled to a respective one of said output ports of a respective one of said optical channel group switches, said protection input port of said second optical protection switch being coupled to a respective one of said output ports of said protection optical channel group switch.
6. A protection switching arrangement as claimed in claim 5 , further comprising a plurality of demultiplexers each including:
a respective input port for receiving a respective one of said optical channel signal groups; and
a respective plurality of output ports for each releasing a respective one of said optical channel signals;
wherein said second optical protection switch includes a plurality of output ports, each of said output ports of said second optical protection switch being coupled to the input port of a respective one of said demultiplexers.
7. A protection switching arrangement as claimed in claim 6 , further comprising a third optical protection switch, coupled to said first layer, for providing in said first layer an alternative switch path for each of said optical channel signals, said first layer comprising:
a plurality of optical channel switches, each including a plurality of input ports; and
a protection optical channel switch including a plurality of input ports;
said third optical protection switch including a plurality of output ports and a protection output port, each of said output ports of said third optical protection switch being coupled to a respective one of said input ports of a respective one of said optical channel switches, said protection output port of said third optical protection switch being coupled to a respective one of said input ports of said protection optical channel switch so as to provide in said first layer said alternative switch path for each of said optical channel signals, said third optical protection switch including a plurality of input ports, each of said input ports of said third optical protection switch being coupled to a respective one of said output ports of a respective one of said demultiplexers.
8. A protection switching arrangement as claimed in claim 5 , further comprising a multiplexer including:
a plurality of input ports for each receiving a respective one of said optical channel signal groups; and
an output port for releasing a composite optical signal;
wherein said second optical protection switch includes a plurality of output ports, each of said output ports of said second optical protection switch being coupled to a respective one of said input ports of said multiplexer.
9. A protection switching arrangement as claimed in claim 1 , wherein said optical protection switch is a first optical protection switch, said protection switching arrangement further comprising a second optical protection switch, coupled to said first layer, for providing in said first layer an alternative switch path for each of said optical channel signals.
10. A protection switching arrangement as claimed in claim 9 , wherein said first layer comprises:
a plurality of optical channel switches, each including a plurality of input ports; and
a protection optical channel switch including a plurality of input ports;
said second optical protection switch including a plurality of output ports and a protection output port, each of said output ports of said second optical protection switch being coupled to a respective one of said input ports of a respective one of said optical channel switches, said protection output port of said second optical protection switch being coupled to one of said input ports of said protection optical channel switch so as to provide in said first layer said alternative switch path for each of said optical channel signals.
11. A protection switching arrangement as claimed in claim 10 , wherein said second optical protection switch includes a plurality of input ports each for coupling to a wavelength converting switch.
12. A protection switching arrangement as claimed in claim 10 , further comprising a third optical protection switch, wherein:
each optical channel switch includes a respective plurality of output ports; and
said protection optical channel switch includes a plurality of output ports;
said third optical protection switch including a plurality of input ports and a protection input port, each of said input ports of said third optical protection switch being coupled to a respective one of said output ports of a respective one of said optical channel switches, said protection input port of said third optical protection switch being coupled to a respective one of said output ports of said protection optical channel switch so as to provide in said first layer said alternative switch path for each of said optical channel signals, said third optical protection switch including a plurality of output ports each for coupling to a wavelength converting switch.
13. A protection switching arrangement as claimed in claim 10 , wherein said second optical protection switch includes a plurality of input ports, each of said input ports of said second optical protection switch being associated with a respective one of said optical channel switches, said second optical protection switch being operative to couple one of its input ports that is associated with a faulty one of the optical channel switches to said protection output port of said second optical protection switch so as to enable said protection optical channel switch to serve as a backup for the faulty one of the optical channel switches.
14. A protection switching arrangement as claimed in claim 1 , wherein said optical protection switch includes a plurality of input ports, each of said input ports of said optical protection switch being associated with a respective one of said optical channel group switches, said optical protection switch being operative to couple one of its input ports that is associated with a faulty one of the optical channel group switches to said protection output port of said optical protection switch so as to enable said protection optical channel group switch to serve as a backup for the faulty one of the optical channel group switches.
15. A switching arrangement comprising:
a first layer for switching a plurality of first optical signals each including a first number of optical channels, said first layer comprising:
a plurality of first optical switches each including a plurality of input ports: and
a first protection optical switch including a plurality of input ports;
a second layer, coupled to said first layer, for switching a plurality of second optical signals each including a second number of optical channels that is different from said first number of optical channels, said second layer comprising:
a plurality of second optical switches each including a plurality of input ports; and
a second protection optical switch including a plurality of input ports;
a protection switching arrangement, coupled to said first layer and said second layer, for providing a first alternative switch path for each of the first optical signals and for providing a second alternative switch path for each of the second optical signals.
16. A switching arrangement as claimed in claim 15 , wherein said protection switching arrangement is responsive to a fault condition in said first layer to redirect through said first alternative switch path at least one of the first optical signals.
17. A switching arrangement as claimed in claim 16 , wherein said protection switching arrangement is responsive to a fault condition in said second layer to redirect through said second alternative switch path at least one of the second optical signals.
18. A switching arrangement as claimed in claim 15 , wherein said second number of optical channels is at least twice said first number of optical channels.