Optical network with repeater at a split-level of the network

• US 5,912,998 A
• Filed: 05/19/1997
• Issued: 06/15/1999
• Est. Priority Date: 11/22/1994
• Status: Expired due to Term

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Quayle, John Alan
• Primary Examiner(s): Lee, John D.
• Assistant Examiner(s): HAO, VICKY D
• Application Number:
  US08/836,701
• Time in Patent Office: 757 Days
• Field of Search: 385/14, 385/24, 359/110, 359/121, 359/123-125, 359/130, 359/143, 359/164-168, 359/137, 359/177, 359/179
• US Class Current: 385/24
• CPC Class Codes: H04B 10/27 Arrangements for networking
• CPC Class Codes: H04B 10/272 Star-type networks or tree-type networks
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging

Abstract

An optical network includes a head-end station connected to a plurality of optical network units via an optical fiber network having a plurality of split levels. One level of split is constituted by a n:1 repeater provided with a monitor for ranging and leveling transmissions from the optical network units.

Claims

1. An optical network comprising:

a head-end station connected to a plurality of optical network units via an optical fibre network having a plurality of split levels,

wherein one level of split in the upstream direction is constituted by a n;

1 repeater provided with monitoring means for ranging and levelling transmissions from the optical network units.

2. An optical network as in claim 1, wherein the repeater is connected to the head-end station by a single optical fibre.

3. An optical network as in claim 2, wherein said single optical fibre has a length of up to 200 km, and the optical network units are spaced from the repeater by distances up to about 8 km.

4. An optical network as in claim 1, wherein:

the repeater includes n receivers and a transmitter,

the transmitter being connected to said head-end station, and

each of the receivers being connected to a respective optical fibre forming part of the network between the repeater and the optical network units.

5. An optical network as in claim 4, wherein the repeater is provided with a multiplexer for multiplexing signals received by the receivers for transmission to the head-end station by the transmitter.

6. An optical network as in claim 1, wherein the repeater includes a plurality of repeater modules each of which is connected to a single optical fibre leading to the head-end station.

7. An optical network as in claim 6, wherein:

each repeater module includes a plurality of receivers and a transmitter,

the transmitter being connected to said single optical fibre, and

each of the receivers being connected to a respective optical fibre forming part of the network between the repeater and the optical network units,

the arrangement being such that the total number of receivers in the repeater modules equals n.

8. An optical network as in claim 7, wherein each repeater module is provided with a multiplexer for multiplexing the signals received by the receivers of that module for transmission to the head-end station by the associated transmitter.

9. An optical network as in claim 8 wherein the repeater includes supervisory means for monitoring the functions of the receivers, the associated multiplexer(s) and the associated transmitter(s).

10. An optical network as in claim 9, wherein:

each receiver includes a pair of parallel receiver boards, and

each transmitter includes a pair of parallel transmitter boards,

the supervisory means of each repeater module being adapted to disconnect one of the receiver boards of each associated pair from its associated optical fibre and to connect the other receiver board of that pair to said associated optical fibre upon detection of a fault in said one receiver board, and is adapted to disconnect one of the associated transmitter boards from said single optical fibre and to connect the other transmitter board of that pair to said single optical fibre on detection of a fault in said one transmitter board.

11. A method for organizing and controlling a head-end station connected to a plurality of optical network units via an optical fibre network having a plurality of split levels, said method comprising:

providing at least one level of split in the upstream direction with a n;

1 repeater; and

ranging and levelling transmissions from the optical network units by monitoring signals received at said at least one level of split.

12. A method as in claim 11 wherein the repeater is connected to the head-end station by a single optical fibre.

13. A method as in claim 11 wherein:

a transmitter is connected to said head-end station, and

one of n receivers is connected to a respective optical fibre forming part of the network between the repeater and the optical network units.

14. A method as in claim 13 including multiplexing signals received by the receivers for transmission to the head-end station by the transmitter.

15. A method as in claim 14 including monitoring functions of the receivers, the associated multiplexer(s) and the associated transmitter(s) at the repeater site.

16. A method as in claim 15 wherein each receiver includes a pair of parallel receiver boards, and each transmitter includes a pair of parallel transmitter boards and including:

disconnecting one of the receiver boards of each associated pair from its associated optical fibre and connecting the other receiver board of that pair to said associated optical fibre upon detection of a fault in said one receiver board, and

disconnecting one of the associated transmitter boards from said single optical fibre and connecting the other transmitter board of that pair to said single optical fibre on detection of a fault in said one transmitter board.