System and Method for Extending Reach in a Passive Optical Network

Abstract

In accordance with the teachings of the present invention, a system and method for extending reach in a passive optical network (PON) is provided. In a particular embodiment, a method for extending reach in a PON includes transmitting traffic at a first wavelength from a transmitter at a first optical network unit (ONU) in a PON and transmitting traffic at a second wavelength from a transmitter at a second ONU in the PON. The method also includes receiving the traffic in the first wavelength at a first input port of a multiplexer at a distribution node in the PON and receiving the traffic in the second wavelength at a second input port of the multiplexer at the distribution node. The method further includes forwarding the traffic in the first wavelength and the traffic in the second wavelength to an optical line terminal (OLT) in the PON.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating an example PSPON;

FIG. 2 is a diagram illustrating an example PSPON providing extended reach in the upstream direction according to a particular embodiment of the invention;

FIG. 3 is a diagram illustrating an example HPON;

FIG. 4 is a diagram illustrating an example HPON providing extended reach in the upstream direction according to a particular embodiment of the invention; and

FIG. 5 is a diagram illustrating an example PON system transmitting optical markers downstream to indicate proper placement of ONUs according to a particular embodiment of the invention.

Claims

1. A method for extending reach in a passive optical network (PON), comprising: transmitting traffic at a first wavelength from a transmitter at a first optical network unit (ONU) in a PON;transmitting traffic at a second wavelength from a transmitter at a second ONU in the PON;receiving the traffic in the first wavelength at a first input port of a multiplexer at a distribution node in the PON;receiving the traffic in the second wavelength at a second input port of the multiplexer at the distribution node; andforwarding the traffic in the first wavelength and the traffic in the second wavelength to an optical line terminal (OLT) in the PON.

2. The method of claim 1, wherein only the traffic in the first wavelength is transmitted at a first time-slot and only the traffic in the second wavelength is transmitted at a second time-slot.

3. The method of claim 2, further comprising receiving the traffic in the first wavelength and the traffic in the second wavelength at a single receiver at the OLT.

4. The method of claim 1, wherein the traffic in the first wavelength and the traffic in the second wavelength are transmitted in the same time-slot.

5. The method of claim 4, further comprising: receiving the traffic in the first wavelength at a first receiver at the OLT; andreceiving the traffic in the second wavelength at a second receiver at the OLT.

6. The method of claim 1, further comprising: transmitting traffic at the first wavelength from a transmitter at a third ONU in the PON; andtransmitting traffic at the second wavelength from a transmitter at a fourth ONU in the PON.

7. The method of claim 1, further comprising: transmitting traffic at the first wavelength only from the first ONU; andtransmitting traffic at the second wavelength only from the second ONU.

8. The method of claim 1, further comprising: receiving traffic in a downstream wavelength at the first ONU; andreceiving traffic in the downstream wavelength at the second ONU.

9. The method of claim 1, further comprising: receiving traffic in a first downstream wavelength at the first ONU; andreceiving traffic in a second downstream wavelength at the second ONU.

10. A system for extending reach in a passive optical network (PON), comprising: a transmitter at a first optical network unit (ONU) in a PON configured to transmit traffic at a first wavelength;a transmitter at a second optical network unit (ONU) in the PON configured to transmit traffic at a second wavelength; anda multiplexer at a distribution node in the PON comprising a first input port and a second input port and configured to: receive the traffic in the first wavelength at the first input port;receive the traffic in the second wavelength at the second input port; andforward the traffic in the first wavelength and the traffic in the second wavelength to an optical line terminal (OLT) in the PON.

11. The system of claim 10, wherein only the transmitter at the first ONU is configured to transmit traffic at a first time-slot and only the transmitter at the second ONU is configured to transmit traffic at a second time-slot.

12. The system of claim 11, further comprising a receiver at the OLT configured to receive the traffic in the first wavelength and the traffic in the second wavelength.

13. The system of claim 10, wherein the transmitter at the first ONU and the transmitter at the second ONU are configured to transmit traffic in the same time-slot.

14. The system of claim 13, further comprising a plurality of receivers at the OLT each configured to receive the traffic in a corresponding one of the first wavelength and the second wavelength.

15. The system of claim 10, further comprising: a transmitter at a third ONU in the PON configured to transmit traffic at the first wavelength; anda transmitter at a fourth ONU in the PON configured to transmit traffic at the second wavelength.

16. The system of claim 10, wherein only the transmitter at the first ONU is configured to transmit at the first wavelength and only the transmitter at the second ONU is configured to transmit at the second wavelength.

17. The system of claim 10, further comprising: a receiver at the first ONU configured to receive traffic in a downstream wavelength; anda receiver at the second ONU configured to receive traffic in the downstream wavelength.

18. The system of claim 10, further comprising: a receiver at the first ONU configured to receive traffic in a first downstream wavelength; anda receiver at the second ONU configured to receive traffic in a second downstream wavelength.

19. A method for extending reach in a passive optical network (PON), comprising: transmitting upstream traffic at a first wavelength in a first time-slot from a first ONU in a PON;transmitting upstream traffic at a second wavelength in a second time-slot from a second ONU in the PON;transmitting upstream traffic at the first wavelength in a third time-slot from a third ONU in the PON;transmitting upstream traffic at the second wavelength in a fourth time-slot from a fourth ONU in the PON, wherein only the traffic in the first wavelength is transmitted in the first time-slot, only the traffic in the second wavelength is transmitted in the second time-slot, only the traffic in the first wavelength is transmitted in the third time-slot, and only the traffic in the second wavelength is transmitted in the fourth time-slot;receiving the upstream traffic in the first wavelength at a first input port of a multiplexer at a distribution node;receiving the traffic in the second wavelength at a second input port of the multiplexer at the distribution node;forwarding the traffic in the first wavelength and the traffic in the second wavelength to an optical line terminal (OLT); andreceiving the traffic in the first wavelength and the traffic in the second wavelength at a single receiver at the OLT.