Optical line terminal arrangement, apparatus and methods

• US 6,721,508 B1
• Filed: 04/19/1999
• Issued: 04/13/2004
• Est. Priority Date: 12/14/1998
• Status: Expired due to Term

• Current Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Original Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Inventors: Gerstel, Ornan A., Ramaswami, Rajiv R.
• Primary Examiner(s): Chan, Jason
• Assistant Examiner(s): SEDIGHIAN, REZA
• Application Number:
  US09/293,775
• Time in Patent Office: 1,821 Days
• Field of Search: 359/124, 359/125, 359/127, 359/128, 359/139, 398/43, 398/45, 398/48, 398/79, 398/82, 398/83
• US Class Current: 398/83
• CPC Class Codes: H04J 14/0201 Add-and-drop multiplexing
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0216 Bidirectional architectures
• CPC Class Codes: H04J 14/022 For interconnection of WDM optical networks
• CPC Class Codes: H04J 14/0278 WDM optical network architectures
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04J 14/0286 WDM hierarchical architectures

Abstract

A wavelength division multiplexed optical communication system includes a plurality of optical line terminals which may be part of separate in service networks, each having a line interface and an all-optical pass-through interface including a plurality of pass-through optical ports, and each also including a plurality of local optical ports which are connectable to client equipment and an optical multiplexer/demultiplexer for multiplexing/demultiplexing optical wavelengths. The optical multiplexer/demultiplexer may include one or more stages for inputting/outputting individual wavelengths or bands of a predetermined number of wavelengths, or a combination of bands and individual wavelengths. At least one of the pass-through optical ports of an optical line terminal of one network may be connected to at least one of the pass-through optical ports of an optical line terminal of another network to form an optical path from the line interface of the optical line terminal of the one network to the line interface of the optical line terminal of the another network to form a merged network. The use of such optical line terminals allows the upgrading and merging of the separate networks while in service.

Claims

1. A wavelength division multiplexed (WDM) optical communication system comprising:

a first optical line terminal comprising;

a line interface to receive from external to the system a first WDM optical signal having multiplexed therein at least one optical wavelength to be locally dropped by the system and at least one pass-through optical wavelength that is not to be locally dropped by the system;

a first demultiplexer to demultiplex from the received first WDM optical signal the at least one optical wavelength to be locally dropped by the system;

a first all-optical pass-through port to which the at least one pass-through wavelength of the received first WDM optical signal is provided optically to the exclusion of the at least one optical wavelength to be locally dropped from the first WDM optical signal, the first all-optical pass-through port residing on a modular card of the system;

a first multiplexer to provide a second WDM optical signal for transmission external to the system; and

a second all-optical pass-through port being optically connected to provide optical pass-through signals received at the second all-optical pass-through port to the first multiplexer for multiplexing, the second all-optical pass-through port residing on a modular card of the system;

a second optical line terminal comprising;

a line interface to receive from external to the system a third WDM optical signal having multiplexed therein at least one optical wavelength to be locally dropped by the system and at least one pass-through optical wavelength that is not to be locally dropped by the system;

a second demultiplexer to demultiplex from the received third WDM optical signal the at least one optical wavelength to be locally dropped by the system;

a third all-optical pass-through port to which the at least one pass-through wavelength of the received third WDM optical signal is provided optically to the exclusion of the at least one optical wavelength to be locally dropped from the third WDM optical signal, the third all-optical pass-through port residing on a modular card of the system that is physically distinct from the modular card on which resides the second all-optical pass through port of the first optical line terminal;

a second multiplexer to provide a fourth WDM optical signal for transmission external to the system; and

a fourth all-optical pass-through port being optically connected to provide optical pass-through signals received at the fourth all-optical pass-through port to the second multiplexer for multiplexing, the fourth all-optical pass-through port residing on a modular card of the system that is physically distinct from the modular card on which resides the first all-optical pass through port of the first optical line terminal;

optical fiber optically connecting the first all-optical pass-through port to the fourth all-optical pass-through port, whereby the system permits the at least one pass-through optical wavelength from the received first WDM optical signal to be further transmitted by the system without any intervening electro-optical conversion by the system of the at least one pass-through optical wavelength; and

optical fiber optically connecting the third all-optical pass-through port to the second all-optical pass-through port, whereby the system permits the at least one pass-through optical wavelength from the received third WDM optical signal to be further transmitted by the system without any intervening electro-optical conversion by the system of the at least one pass-through optical wavelength.

2. The WDM optical communication system of claim 1, wherein at least one of the first and second optical line terminals interface with an external fiber facility in a bidirectional manner to transmit and receive the corresponding WDM optical signals.

3. The WDM optical system of claim 2, wherein the first and second all-optical pass-through ports reside on the same modular card of the system.

4. The WDM optical system of claim 3, wherein the first and second all-optical pass-through ports are in common with one another such that that the at least one pass-through wavelength of the received first WDM optical signal and the at least one pass-through wavelength of the received third WDM optical signal are provided to a common all-optical pass-through port in a bidirectional manner.

5. The WDM optical system of claim 2, wherein the first and second all-optical pass-through ports reside on the same modular card of the system, and wherein the third and fourth all-optical pass-through ports reside on the same modular card of the system.

6. The WDM optical system of claim 5, wherein the first and second all-optical pass-through ports are in common with one another such that that the at least one pass-through wavelength of the received first WDM optical signal and the at least one pass-through wavelength of the received third WDM optical signal are provided to a first common all-optical pass-through port in a bidirectional manner, and wherein the third and fourth all-optical pass-through ports are in common with one another such that that the at least one pass-through wavelength of the received first WDM optical signal and the at least one pass-through wavelength of the received third WDM optical signal are provided to a second common all-optical pass-through port in a bidirectional manner.

7. The WDM optical system of claim 1, wherein the first optical line terminal demultiplexes the first WDM optical signal into at least one individual constituent optical wavelength of the first WDM optical signal and provides the at least one individual constituent optical wavelength to the first all-optical pass-through port as the at least one pass-through optical wavelength that is not to be locally dropped by the system.

8. The WDM optical system of claim 7, wherein each of the first and second optical line terminals further comprises a corresponding plurality of 1×

N optical switches wherein each optical switch directs a demultiplexed individual constituent wavelength to an all-optical pass-through port when the switch is in a first mode, and alternatively directs the demultiplexed individual constituent wavelength away from an all-optical pass-through port when the switch is in a second mode.

9. The WDM optical system of claim 1, wherein the first optical line terminal demultiplexes the first WDM optical signal into at least one optical band and provides the at least one optical band to the first all-optical pass-through port as the at least one pass-through optical wavelength that is not to be locally dropped by the system.

10. The WDM optical system of claim 1, wherein the first and second all-optical pass-through ports reside on the same modular card of the system.

11. The WDM optical system of claim 10, wherein the first and second all-optical pass-through ports are in common with one another such that that the at least one pass-through wavelength of the received first WDM optical signal and the at least one pass-through wavelength of the received third WDM optical signal are provided to a common all-optical pass-through port in a bidirectional manner.

12. The WDM optical system of claim 1, wherein the first and second all-optical pass-through ports reside on the same modular card of the system, and wherein the third and fourth all-optical pass-through ports reside on the same modular card of the system.

13. The WDM optical system of claim 12, wherein the first and second all-optical pass-through ports are in common with one another such that that the at least one pass-through wavelength of the received first WDM optical signal and the at least one pass-through wavelength of the received third WDM optical signal are provided to a first common all-optical pass-through port in a bidirectional manner, and wherein the third and fourth all-optical pass-through ports are in common with one another such that that the at least one pass-through wavelength of the received first WDM optical signal and the at least one pass-through wavelength of the received third WDM optical signal are provided to a second common all-optical pass-through port in a bidirectional manner.

14. A wavelength division multiplexed (WDM) optical communication system comprising:

a first optical line terminal comprising;

a line interface to receive from external to the system a first WDM optical signal having multiplexed therein at least one optical wavelength to be locally dropped by the system and at least one pass-through optical wavelength that is not to be locally dropped by the system;

a first demultiplexer to demultiplex from the received first WDM optical signal the at least one optical wavelength to be locally dropped by the system;

a first all-optical pass-through port to which the at least one pass-through wavelength of the received first WDM optical signal is provided optically to the exclusion of the at least one optical wavelength to be locally dropped from the first WDM optical signal;

a first multiplexer to provide a second WDM optical signal for transmission external to the system; and

a second all-optical pass-through port being optically connected to provide optical pass-through signals received at the second all-optical pass-through port to the first multiplexer for multiplexing;

a second optical line terminal that is physically distinct from the first optical line terminal, comprising;

a line interface to receive from external to the system a third WDM optical signal having multiplexed therein at least one optical wavelength to be locally dropped by the system and at least one pass-through optical wavelength that is not to be locally dropped by the system;

a second demultiplexer to demultiplex from the received third WDM optical signal the at least one optical wavelength to be locally dropped by the system;

a third all-optical pass-through port to which the at least one pass-through wavelength of the received third WDM optical signal is provided optically to the exclusion of the at least one optical wavelength to be locally dropped from the third WDM optical signal;

a second multiplexer to provide a fourth WDM optical signal for transmission external to the system; and

a fourth all-optical pass-through port being optically connected to provide optical pass-through signals received at the fourth all-optical pass-through port to the second multiplexer for multiplexing;

optical fiber optically connecting the first all-optical pass-through port to the fourth all-optical pass-through port, whereby the system permits the at least one pass-through optical wavelength from the received first WDM optical signal to be further transmitted by the system without any intervening electro-optical conversion by the system of the at least one pass-through optical wavelength; and

optical fiber optically connecting the third all-optical pass-through port to the second all-optical pass-through port, whereby the system permits the at least one pass-through optical wavelength from the received third WDM optical signal to be further transmitted by the system without any intervening electro-optical conversion by the system of the at least one pass-through optical wavelength.

15. The WDM optical communication system of claim 14, wherein at least one of the first and second optical line terminals interface with an external fiber facility in a bidirectional manner to transmit and receive the corresponding WDM optical signals.

16. The WDM optical system of claim 14, wherein the first optical line terminal demultiplexes the first WDM optical signal into at least one individual constituent optical wavelength of the first WDM optical signal and provides the at least one individual constituent optical wavelength to the first all-optical pass-through port as the at least one pass-through optical wavelength that is not to be locally dropped by the system.

17. The WDM optical system of claim 16, wherein each of the first and second optical line terminals further comprises a corresponding plurality of 1×

N optical switches wherein each optical switch directs a demultiplexed individual constituent wavelength to an all-optical pass-through port when the switch is in a first mode, and alternatively directs the demultiplexed individual constituent wavelength away from an all-optical pass-through port when the switch is in a second mode.

18. The WDM optical system of claim 14, wherein the first optical line terminal demultiplexes the first WDM optical signal into at least one optical band and provides the at least one optical band to the first all-optical pass-through port as the at least one pass-through optical wavelength that is not to be locally dropped by the system.

19. A wavelength division multiplexed (WDM) optical communication system comprising:

a first optical line terminal comprising;

a line interface to receive from external to the system a first WDM optical signal having multiplexed therein at least one optical wavelength to be locally dropped by the system and at least one pass-through optical wavelength that is not to be locally dropped by the system;

a first demultiplexer to demultiplex from the received first WDM optical signal the at least one optical wavelength to be locally dropped by the system;

a first all-optical pass-through port to which the at least one pass-through wavelength of the received first WDM optical signal is provided optically, the first all-optical pass-through port residing on a first modular card;

a first multiplexer to provide a second WDM optical signal for transmission external to the system; and

a second all-optical pass-through port residing on the first modular card, the second all-optical pass-through port being optically connected to provide optical pass-through signals received at the second all-optical pass-through port to the first multiplexer for multiplexing;

a second optical line terminal comprising;

a line interface to receive from external to the system a third WDM optical signal having multiplexed therein at least one optical wavelength to be locally dropped by the system and at least one pass-through optical wavelength that is not to be locally dropped by the system;

a second demultiplexer to demultiplex from the received third WDM optical signal the at least one optical wavelength to be locally dropped by the system;

a third all-optical pass-through port to which the at least one pass-through wavelength of the received third WDM optical signal is provided optically, the third all-optical pass-through port residing on a second modular card that is physically distinct from the first modular card;

a second multiplexer to provide a fourth WDM optical signal for transmission external to the system; and

a fourth all-optical pass-through port residing on the second modular card, the fourth all-optical pass-through port being optically connected to provide optical pass-through signals received at the fourth all-optical pass-through port to the second multiplexer for multiplexing;

optical fiber optically connecting the first all-optical pass-through port on the first modular card to the fourth all-optical pass-through port on the second modular card, whereby the system permits the at least one pass-through optical wavelength from the first WDM optical signal to be further transmitted by the system without any intervening electro-optical conversion of the at least one pass-through optical wavelength; and

optical fiber optically connecting the third all-optical pass-through port on the second modular card to the second all-optical pass-through port on the first modular card, whereby the system permits the at least one pass-through optical wavelength from the third WDM optical signal to be further transmitted by the system without any intervening electro-optical conversion of the at least one pass-through optical wavelength.

20. The WDM optical communication system of claim 19, wherein at least one of the first and second optical line terminals interface with an external fiber facility in a bidirectional manner to transmit and receive the corresponding WDM optical signals.

21. The WDM optical system of claim 19, wherein the first optical line terminal demultiplexes the first WDM optical signal into at least one individual constituent optical wavelength of the first WDM optical signal and provides the at least one individual constituent optical wavelength to the first all-optical pass-through port as the at least one pass-through optical wavelength that is not to be locally dropped by the system.

22. The WDM optical system of claim 21, wherein each of the first and second optical line terminals further comprises a corresponding plurality of 1×

N optical switches wherein each optical switch directs a demultiplexed individual constituent wavelength to an all-optical pass-through port when the switch is in a first mode, and alternatively directs the demultiplexed individual constituent wavelength away from an all-optical pass-through port when the switch is in a second mode.

23. The WDM optical system of claim 19, wherein the first optical line terminal demultiplexes the first WDM optical signal into at least one optical band and provides the at least one optical band to the first all-optical pass-through port as the at least one pass-through optical wavelength that is not to be locally dropped by the system.