Method and devices for automatic tuning in WDM-PON

Patent metadata

Field	Value
Publication number	US-9660754-B2
Application number	US-200913257706-A
Country	US
Kind code	B2
Filing date	Mar 20, 2009
Priority date	Mar 20, 2009
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A system and method in a wavelength division multiplexing passive optical network is provided. A multiplexed optical downstream signal is transmitted from an optical line terminal to a passive distribution node. The signal is demultiplexed into a plurality of optical sub-signals. A sub-signal is transferred to an optical network termination. The received at least one sub-signal is identified. An optical wavelength of an upstream optical signal is set as a function of a predefined relationship between an optical wavelength of the received at least one sub-signal and the optical wavelength of the upstream signal. The upstream signal is transmitted to the optical line terminal via the passive distribution node.

First claim

The invention claimed is:

1. A method in an optical network termination for use in a wavelength division multiplexing passive optical system, the method comprising:
receiving one optical sub-signal extracted from a multiplexed optical downstream signal that was transmitted from an optical line terminal via a passive distribution node,
identifying the received sub-signal,

and the method characterized in:
setting an optical wavelength of an upstream optical signal as a function of a predefined relationship between an optical wavelength of the received sub-signal and the optical wavelength of the upstream signal, wherein the predefined wavelength relationship is implemented as a difference in filtering properties of a filter device for the identifying of the received sub-signal and a filter device for the setting of the wavelength of the upstream signal, and
transmitting the upstream signal to the optical line terminal via the passive distribution node.

2. A method according to claim 1 , wherein the predefined wavelength relationship comprises a predefined wavelength difference between the wavelength of the downstream sub-signal and the wavelength of the upstream signal.

3. A method according to claim 1 , wherein the predefined wavelength relationship comprises a predefined association between the wavelength of the upstream signal and the wavelength of the downstream sub-signal.

4. A method according to claim 1 , wherein the identifying of the wavelength of the received at least one sub-signal comprises tuning a filter configured to sweep the wavelength range of the downstream sub-signal.

5. A method according to claim 1 , wherein the setting of the wavelength of the upstream signal comprises tuning a filter configured to filter light from a light source.

6. An optical network termination for use in a wavelength division multiplexing passive optical network, comprising:
a receiver for receiving one optical sub-signal extracted from a multiplexed optical downstream signal that was transmitted from an optical line terminal via a passive distribution node,
an optical signal identifier configured to identify the received sub-signal, the optical network termination characterized in that it comprises:
a processor configured to set the wavelength of an upstream optical signal as a function of a predefined relationship between an optical wavelength of the received sub-signal and the optical wavelength of the upstream signal, wherein the predefined wavelength relationship is implemented as a difference in filtering properties of a filter device for the identifying of the received sub-signal and a filter device for the setting of the wavelength of the upstream signal, and
a transmitter configured to transmit the upstream signal to the optical line terminal via the passive distribution node.

7. A wavelength division multiplexing passive optical network system, comprising:
an optical line terminal for transmitting a multiplexed optical downstream signal to an input port of a passive distribution node,
a demultiplexer at the passive distribution node, for demultiplexing the signal into a plurality of optical sub-signals,
an optical network termination according to claim 6 , and
an output port at the passive distribution node, for transferring one of the sub-signals to the optical network termination.

Assignees

• Dahlfort Stefan
• Ohlen Peter
• ERICSSON TELEFON AB L M (publ)

Inventors

• Dahlfort Stefan
• Ohlen Peter

Classifications

• H04J14/0282

  WDM tree architectures · CPC title

• H04J14/0226 Primary

  Fixed carrier allocation, e.g. according to service · CPC title