Optical transmission device and wavelength-multiplexed optical transmission system

• US 6,449,070 B1
• Filed: 01/27/1999
• Issued: 09/10/2002
• Est. Priority Date: 02/16/1998
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Izumi, Futoshi
• Primary Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US09/237,904
• Time in Patent Office: 1,322 Days
• Field of Search: 359/110, 359/124, 359/337
• US Class Current: 398/79
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04J 14/0241 Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
• CPC Class Codes: H04J 14/0278 WDM optical network architectures

Abstract

An optical transmission device that can be applied to a wavelength-multiplexed optical transmission system includes a first part creating a supervisory control signal to be transmitted in optical formation together with an optical main signal, the supervisory control signal comprising a vector of elements respectively corresponding to wavelengths. The device further includes a second part converting a vector included in a supervisory control signal received from a remote optical transmission device into another vector by a process using a path matrix in the vector received forms diagonal elements of the path matrix, the above another vector being transmitted to a next stage in the wavelength-multiplexed optical transmission system.

Claims

1. An optical transmission device for a wavelength division multiplexed (WDM) optical transmission system, said optical transmission device comprising:

a first part creating a supervisory control signal and transmitting the created supervisory control signal together with an optical main signal, the supervisory control signal including a vector of elements respectively corresponding to wavelengths of the WDM optical transmission system; and

a second part receiving a supervisory control signal, different from the transmitted supervisory control signal, from a remote optical transmission device, the received supervisory control signal including a vector, the second part converting the vector included in the received supervisory control signal into another vector via a path matrix in which the vector included in the received supervisory control signal forms diagonal elements, said another vector being transmitted by the optical transmission device to a next stage in the WDM optical transmission system.

2. The optical transmission device as claimed in claim 1, further comprising a third part which transmits a wavelength information vector to the next stage in the WDM optical transmission system, the wavelength information vector indicating that the number of wavelengths used by the optical transmission device is zero when the transmitted supervisory control signal and the main signal are broken down.

3. The optical transmission device as claimed in claim 1, wherein:

the vector included in the transmitted supervisory control signal is a wavelength information vector which indicates the number of wavelengths used in the main signal; and

the optical transmission device or said remote optical transmission device comprises a part which determines whether there is a collision of wavelengths used by referring to wavelength information vectors received from a plurality of routes.

4. The optical transmission device as claimed in claim 1, wherein the optical transmission device receives a supervisory control signal from a transmission-side device including a vector of elements corresponding to wavelengths transmitted by the transmission-side device to the optical transmission device, the optical transmission device further comprising:

a third part which transmits a supervisory control signal to the transmission-side device including a received-state vector indicating wavelengths transmitted by the transmission-side device which were normally received by the optical transmission device.

5. The optical transmission device as claimed in claim 1, wherein the optical transmission device receives a supervisory control signal from a transmission-side device including a vector of elements corresponding to wavelengths transmitted by the transmission-side device to the optical transmission device, the optical transmission device further comprising:

a third part which transmits to the transmission-side device a supervisory control signal including a received-state vector formed by performing an OR operation on received-state vectors received from more than one route.

6. The optical transmission device as claimed in claim 1, wherein the optical transmission device receives a supervisory control signal from a transmission-side device including a vector of elements corresponding to wavelengths transmitted by the transmission-side device to the optical transmission device, the optical transmission device further comprising:

a third part which transmits to the transmission-side device a supervisory control signal including a received-state vector formed by performing an AND operation on received-state vectors received from more than one route.

7. The optical transmission device as claimed in claim 1, further comprising a third part comparing a wavelength information vector indicating wavelengths used with a received-state vector indicating wavelengths normally received, and identifying a fault from a mismatch between corresponding elements in the wavelength information vector and the received-stage vector.

8. The optical transmission device as claimed in claim 1, further comprising a transmission device which uses a supervisory control signal to transmit a wavelength retrieving vector for retrieving a usable wavelength and, in response, receives a return supervisory control signal from an optical device in the WDM optical transmission system including a retrieval result indicating a retrieved usable wavelength and a device ID.

9. The optical transmission device as claimed in claim 1, wherein the optical transmission devices uses a supervisory control signal to transmit a wavelength retrieving vector for retrieving a usable wavelength and, in response, receives a return supervisory control signal from an optical device in the WDM optical transmission system including a retrieval result indicating a retrieved usable wavelength, a device ID and a counter value indicating an order of receipt of the wavelength retrieving vector.

10. The optical transmission device as claimed in claim 1, further comprising a receiving direction memory part which stores a direction in which a wavelength retrieving vector indicating a usable wavelength is received, and a direction in which a response is received, the response being sent in receipt of a newly created wavelength information vector.

11. The optical transmission device as claimed in claim 1, further comprising

a receiving direction memory part which stores a direction in which a wavelength retrieving vector indicating a usable wavelength is received, and a direction in which a response is received, the response being sent in receipt of a newly created wavelength information vector;

and

a part which resets the receiving direction memory part after the optical transmission device is controlled to use the usable wavelength in accordance with a route switching instruction.

12. The optical transmission device as claimed in claim 1, further comprising a third part which sends, by a supervisory control signal, a wavelength retrieving vector for retrieving a usable wavelength, and a route switching instruction indicating whether the usable wavelength should be used by switching.

13. The optical transmission device as claimed in claim 1, further comprising a third part which performs setting of a network side or a terminal side on the basis of a magnitude of a value of a device ID of an opposing optical transmission device at the time of establishing a data link for sending and receiving supervisory control signals.

14. An optical amplifier receiving a wavelength division multiplexed (WDM) optical signal and a supervisory signal transmitted by an optical transmission device, the supervisory signal including a wavelength information vector indicating wavelengths used by the WDM optical signal, the optical amplifier comprising:

a first part which optically amplifies the received WDM optical signal; and

an automatic level controller performing automatic level control based on the number of wavelengths indicated by the received wavelength information vector.

15. The optical amplifier as claimed in claim 14, wherein the automatic level controller performs automatic level control so that, when the supervisory control signal is broken down, automatic level control is based on a number of wavelengths used immediately before the supervisory control signal broke down.

16. The optical amplifier as claimed in claim 14, wherein the automatic level controller performs automatic level control so that, when the supervisory control signal and the WDM optical signal are broken down, automatic level control is based on a condition in which the number of wavelengths used in the WDM optical signal is equal to zero.

17. The optical amplifier as claimed in claim 14, wherein the optical amplifier comprises a part which gradually controls an output level based on an increase or decrease in the number of wavelengths used in response to a notification indicating such an increase or decrease and returns the output level to an original level based on the number of wavelengths used before said increase or decrease when a fault occurs while gradually controlling the output level, the optical amplifier being notified of the fault by the supervisory control signal.

18. A wavelength-multiplexed optical transmission system comprising:

a plurality of optical transmission devices, each of the optical transmission devices comprising

a first part creating a supervisory control signal and transmitting the created supervisory control signal together with an optical main signal, the supervisory control signal including elements respectively corresponding to wavelengths of the wavelength-multiplexed optical transmission system, and

a second part receiving a supervisory control signal, different from the transmitted supervisory control signal, from a remote optical transmission device, the received supervisory control signal including a vector, the second part converting the vector included in the received supervisory control signal into another vector via a path matrix in which the vector included in the received supervisory control signal forms diagonal elements, said another vector being transmitted by the optical transmission device to a next stage in the wavelength-multiplexed optical transmission system.

19. The wavelength-multiplexed optical transmission system as claimed in claim 18, wherein:

one of the optical transmission devices serves as a master station, and remaining optical transmission devices serve as slave stations;

a path retrieval or a route retrieval using a wavelength retrieving vector is carried out by the master station or one of the slave stations which is allowed to perform the path retrieval or the route retrieval by the master station; and

one of the slave stations is set to a new master station if a fault occurs in the master station.

20. An apparatus comprising:

an optical transmission device comprising

a transmitter creating a supervisory control signal and transmitting the created supervisory control signal together with a wavelength divisional multiplexed (WDM) optical signal to an optical transmission line of a WDM optical transmission system for transmission through the transmission line, the supervisory control signal including a vector of elements respectively corresponding to wavelengths of the WDM optical transmission system; and

a receiver receiving a supervisory control signal, different from the transmitted supervisory control signal, from a remote optical transmission device, the received supervisory control signal including a vector, the receiver converting the vector included in the received supervisory control signal into another vector via a path matrix in which the vector included in the received supervisory control signal forms diagonal elements, said another vector being transmitted by the optical transmission device to a next stage in the WDM optical transmission system.

21. An apparatus as in claim 20, wherein the vector included in the supervisory control signal transmitted with the WDM optical signal is a wavelength information vector indicating the number of wavelengths used in the WDM optical signal.

22. An apparatus comprising:

an optical transmission device comprising

means for creating a supervisory control signal and for transmitting the created supervisory control signal together with a wavelength divisional multiplexed (WDM) optical signal to an optical transmission line of a WDM optical transmission system for transmission through the transmission line, the supervisory control signal including a vector of elements respectively corresponding to wavelengths of the WDM optical transmission system,

means for receiving a supervisory control signal, different from the transmitted supervisory control signal, from a remote optical transmission device, the received supervisory control signal including a vector,

means for converting the vector included in the received supervisory control signal into another vector via a path matrix in which the vector included in the received supervisory control signal forms diagonal elements, and

means for transmitting said another vector to a next stage in the WDM optical transmission system.

23. An apparatus as in claim 22, wherein the vector included in the supervisory control signal transmitted with the WDM optical signal is a wavelength information vector indicating the number of wavelengths used in the WDM optical signal.

24. A method comprising:

creating a supervisory control signal;

transmitting the created supervisory control signal together with a wavelength divisional multiplexed (WDM) optical signal to an optical transmission line of a WDM optical transmission system for transmission through the transmission line, the supervisory control signal including a vector of elements respectively corresponding to wavelengths of the WDM optical transmission system;

receiving a supervisory control signal, different from the transmitted supervisory control signal, from a remote optical transmission device, the received supervisory control signal including a vector;

converting the vector included in the received supervisory control signal into another vector via a path matrix in which the vector included in the received supervisory control signal forms diagonal elements; and

transmitting said another vector to a next stage in the WDM optical transmission system.

25. A method as in claim 24, wherein the vector included in the supervisory control signal transmitted with the WDM optical signal is a wavelength information vector indicating the number of wavelengths used in the WDM optical signal.