WDM PON protection scheme using a dual port arrayed waveguide grating (AWG)
View Patent ↗A Wavelength Division Multiplexed Passive Optical Network (WDM-PON) includes an Optical Line Terminal (OLT) including a first Arrayed Waveguide Grating (AWG) MUX/DEMUX, and a remote node including a second AWG MUX/DEMUX. Each AWG MUX/DEMUX has at least two input ports for receiving a respective wavelength division multiplexed optical signal, and a plurality of output ports. Each output port of the Optical Line Terminal AWG MUX/DEMUX is coupled to a respective transceiver of the OLT. Each output port of the remote node AWG MUX/DEMUX is coupled to a respective PON having at least one optical network terminal (ONT). Respective first and second optical paths are coupled between corresponding input ports of the first and second AWG MUX/DEMUXs. Means are provided for sourcing seed light of the WDM-PON into a selected one the first and second optical paths.
1. A Wavelength Division Multiplexed Passive Optical Network (WDM-PON) comprising:
an Optical Line Terminal (OLT) including a first Arrayed Waveguide Grating (AWG) MUX/DEMUX comprising at least two input ports, each receiving optical signals of different wavelengths, and a plurality of output ports, each output port being coupled to a respective transceiver of the OLT;
a remote node including a second AWG MUX/DEMUX comprising at least two input ports for receiving the optical signals of different wavelengths, and a plurality of output ports, each output port of the second AWG MUX/DEMUX being coupled to a respective PON having at least one optical network terminal (ONT); and
respective first and second optical paths coupled between corresponding input ports of the first and second AWG MUX/DEMUXs, wherein:
seed light of the WDM-PON is input into at least one of the first or second optical paths,
a first wavelength mapping is defined between a first port of the first AWG and the output ports of the first AWG,
a second wavelength mapping is defined between a second port of the first AWG and the output ports of the first AWG,
the first and second wavelength mappings are different, and
the first and second optical paths are enabled at different times to carry the optical signals of different wavelengths, the first optical path carrying the optical signals of different wavelengths based on the first wavelength mapping and the second optical path carrying the optical signals of different wavelengths based on the second wavelength mapping.
2. The network as claimed in claim 1 , further comprising:
independent Broadband Light Sources (BLSs) optically coupled to respective ones of the first and second optical paths.
3. The network as claimed in claim 2 , wherein the each of the independent Broadband Light Sources (BLSs) comprises a C-band BLS for seeding uplink signals and an L-band BLS for seeding downlink signals.
4. The network as claimed in claim 1 , further comprising:
a pair of optical switches coupled to the first and second optical paths; and
a Broadband Light Source (BLS), the optical switches being controlled to optically couple the BLS to the first or second optical paths at different times.
5. The network as claimed in claim 4 , wherein the Broadband Light Sources (BLSs) comprises a C-band BLS for seeding uplink signals and an L-band BLS for seeding downlink signals.
6. The network as claimed in claim 1 , wherein:
the second signal path is disabled when the first signal path is enabled, and
the first signal path is disabled when the second signal path is enabled.
7. The network as claimed in claim 6 , wherein the second signal path is enabled and the first signal path is disabled when a failure is detected along the first signal path.
8. The network as claimed in claim 7 , wherein the failure includes a failure of a light source that provides seed light to the first signal path.
9. The network as claimed in claim 7 , wherein the failure includes a failure in a signal carrying medium along the first signal path.
10. The network as claimed in claim 1 , wherein:
the first wavelength mapping is offset by one or more wavelengths from the second wavelength mapping.
11. The network as claimed in claim 1 , wherein:
the first signal path includes one or more first seed light sources, and
the second signal path includes one or more second seed light sources different from the one or more of the first seed light sources.
12. The network as claimed in claim 1 , wherein the first and second signal paths are coupled to one or more same seed light sources.
13. An apparatus comprising:
an input interface to receive optical signals of different wavelengths; and
an output interface coupled to the input interface, wherein:
a first mapping is defined between the optical signal wavelengths received by the input interface and optical signal wavelengths of the output interface;
a second mapping is defined between the optical signal wavelengths received by the input interface and the optical signal wavelengths of the output interface,
the first and second wavelength mappings are different, and
optical signals are output from the output interface based on at least one of the first or second mappings, wherein the output interface has:
a first output port to receive the optical signals of different wavelengths, and
a second output port to receive the optical signals of different wavelengths,
wherein the first output port outputs the optical signals of different wavelengths along a first signal path based on the first mapping and the second output port outputs the optical signals of different wavelengths along a second signal path based on the second mapping, and wherein:
the optical signals of different wavelengths are output along the first signal path based on the first mapping when the second signal path is disabled, and
the optical signals of the different wavelengths are output along the second signal path based on the second mapping with the first signal path is disabled.
14. The apparatus as claimed in claim 13 , wherein the first wavelength mapping is offset by one or more wavelengths from the second wavelength mapping.
15. The apparatus as claimed in claim 13 , wherein the input interface includes a plurality of input ports.
16. The apparatus of claim 15 , wherein each of the plurality of input ports receives the optical signals of different wavelengths.
17. The apparatus as claimed in claim 16 , wherein each of the plurality of input ports receives a same number of the optical signals of the different wavelengths.
18. The apparatus as claimed in claim 13 , wherein the output interface outputs the optical signals of different wavelengths along different signal paths.
19. The apparatus as claimed in claim 13 , wherein the optical signals of different wavelengths are output along different signal paths at different times.
20. The apparatus as claimed in claim 13 , wherein the first signal path is disabled based on a first predetermined condition and the second signal path is disabled based on a second predetermined condition.
21. The apparatus as claimed in claim 20 , wherein the first and second predetermined conditions are different conditions.
22. The apparatus as claimed in claim 21 , wherein the first and second predetermined conditions correspond to detection of failures in different seed light sources.
23. The apparatus as claimed in claim 21 , wherein the first and second predetermined conditions correspond to detection of failures in different mediums used to transport the optical signals along respective ones of the first and second signal paths.
24. The apparatus as claimed in claim 13 , wherein the first signal path and the second signal path are enabled at different times.
25. A network terminal comprising the apparatus of claim 13 .