US 9,755,746 B1Granted

Systems and methods for digitally splitting an optical line terminal across multiple fibers

AssigneeAdtran, Inc.

InventorThomas Frederick Detwiler

Life of this patent

Estimating the term…

Loading patent…

Abstract

The physical layer of an optical line terminal (OLT) of an optical network is split across multiple fibers so that the OLT has a plurality of optical transceivers for respectively communicating across a plurality of optical fibers. Thus, each optical transceiver is in communication with a smaller number of optical network units (ONUs) relative to an embodiment for which a single optical transceiver is employed, thereby reducing the transmit power requirements of the optical network. Accordingly, less expensive optical components, such as lasers, can be used at the OLT and the ONUs. In addition, the split at the OLT is implemented digitally, and the digital components of the OLT are arranged such that various performance benefits are realized. As an example, the OLT may be configured such that data and/or overhead may be simultaneously transmitted in the upstream direction thereby increasing the upstream throughput and capacity of the optical network.

Claims27

Dependent claims

An optical line terminal, comprising:

a first optical transceiver configured to transmit a downstream optical signal across a first optical fiber coupled to the first optical transceiver, the first optical transceiver further configured to receive a first burst transmission from the first optical fiber;
a second optical transceiver configured to transmit the downstream optical signal across a second optical fiber coupled to the second optical transceiver, the second optical transceiver further configured to receive a second burst transmission from the second optical fiber;
a first burst-transmission recovery element coupled to the first optical transceiver and configured to receive the first burst transmission from the first optical transceiver, the first burst-transmission recovery element configured to recover a first media access control-layer (MAC-layer) payload portion of the first burst transmission based on a first preamble and a first delimiter of the first burst transmission, the first burst-transmission recovery element configured to strip the first preamble and the first delimiter from the first MAC-layer payload portion and to transmit first digital words defining the first MAC-layer payload portion;
first upstream circuitry configured to buffer a plurality of data packets of the first MAC-layer payload portion based on the first digital words;
and
a second burst-transmission recovery element coupled to the second optical transceiver and configured to receive the second burst transmission from the second optical transceiver, the second burst-transmission recovery element configured to recover a second MAC-layer payload portion of the second burst transmission based on a second preamble and a second delimiter of the second burst transmission, the second burst-transmission recovery element configured to strip the second preamble and the second delimiter from the second MAC-layer payload portion and to transmit second digital words defining the second MAC-layer payload portion.

3 more elements

An optical line terminal, comprising:

a first optical transceiver configured to transmit a downstream optical signal across a first optical fiber coupled to the first optical transceiver, the first optical transceiver further configured to receive a first burst transmission from the first optical fiber;
a second optical transceiver configured to transmit the downstream optical signal across a second optical fiber coupled to the second optical transceiver, the second optical transceiver further configured to receive a second burst transmission from the second optical fiber;
a first burst-transmission recovery element coupled to the first optical transceiver and configured to receive the first burst transmission from the first optical transceiver, the first burst-transmission recovery element configured to synchronize to the first burst transmission based on a first media access control-layer (MAC-layer) overhead portion of the first burst transmission and to transmit first digital words defining a first MAC-layer payload portion of the first burst transmission;
first upstream circuitry configured to buffer a plurality of data packets of the first MAC-layer payload portion based on the first digital words;
a second burst-transmission recovery element coupled to the second optical transceiver and configured to receive the second burst transmission from the second optical transceiver, the second burst-transmission recovery element configured to synchronize to the second burst transmission based on a second MAC-layer overhead portion of the second burst transmission and to transmit second digital words defining a second MAC-layer payload portion of the second burst transmission;
and
a control element configured to control a timing of the first and second burst transmissions across the first and second optical fibers, respectively, such that the first MAC-layer overhead portion overlaps with the second burst transmission.

4 more elements

A method for use at an optical line terminal, comprising:

transmitting a downstream optical signal across a first optical fiber via a first optical transceiver of the optical line terminal;
transmitting the downstream optical signal across a second optical fiber via a second optical transceiver of the optical line terminal;
receiving a first burst transmission from the first optical fiber via the first optical transceiver;
receiving a second burst transmission from the second optical fiber via the second optical transceiver;
recovering a first media access control-layer (MAC-layer) payload portion of the first burst transmission via a first burst-transmission recovery element based on a first MAC-layer overhead portion of the first burst transmission;
buffering a plurality of data packets of the first MAC-layer payload portion subsequent to the recovering the first MAC-layer payload portion;
recovering a second MAC-layer payload portion of the second burst transmission via a second burst-transmission recovery element based on a second MAC-layer overhead portion of the second burst transmission;
buffering a plurality of data packets of the second MAC-layer payload portion subsequent to the recovering the second MAC-layer payload portion;
and
controlling a timing of the first and second burst transmissions across the first and second optical fibers, respectively, such that the first MAC-layer overhead portion overlaps with the second burst transmission.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/505,677Filed 3 Oct 2014
Granted: 5 Sep 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H04B 10/2575
Arrangements specific to fibre transmission: radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
H04B 10/27
Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing…
H04B 10/272
Arrangements for networking: star-type networks or tree-type networks
H04B 10/40
Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing…