Multi-drop optical communication

• US 8,965,204 B2
• Filed: 05/10/2012
• Issued: 02/24/2015
• Est. Priority Date: 05/10/2011
• Status: Active Grant

• Current Assignee: Schneider Electric Systems USA, Inc. (Schneider Electric SE)
• Original Assignee: Invensys Systems Incorporated (Invensys PLC)
• Inventors: Camino, Nestor J. Jr., Kagan, Harris D.
• Primary Examiner(s): Bello, Agustin
• Application Number:
  US13/468,822
• Publication Number:
  US 20120288281A1
• Time in Patent Office: 1,020 Days
• Field of Search: 398106-113, 398/58, 398/59, 398/135, 398/139
• US Class Current: 398/58
• CPC Class Codes: G02B 6/421 the intermediate optical component consisting of a short length of fibre, e.g. fibre stub
• CPC Class Codes: G02B 6/4215 the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers G02B6/4246 takes precedence
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: G02B 6/429 by surface irregularities on the light guide, e.g. by mechanical modification of the surface of the light guide on its exterior
• CPC Class Codes: G02B 6/4291 by accessing the evanescent field of the light guide
• CPC Class Codes: H04B 10/278 Bus-type networks

Abstract

An optical communication system including an optical communication fiber and a plurality of modules. Each of the modules has an optical transceiver that is optically coupled to the optical communication fiber by a corresponding optical drop. And each of the transceivers is configured for transmitting and/or receiving one or more optical signals via the optical communication fiber. The optical signals represent a plurality of individual data streams formatted according to one or more different communication protocols. In this manner, optical communication is enabled among the modules via the optical communication fiber.

Claims

1. An optical communication system comprising:

an optical communication fiber; and

a plurality of modules, each of said modules comprising an optical transceiver, said optical transceiver being optically coupled to the optical communication fiber by a corresponding drop and configured for transmitting and/or receiving one or more optical signals via the optical communication fiber, said optical signals comprising frequency encoded data and representing a plurality of individual data streams formatted according to a plurality of different communication protocols, wherein the optical signals are frequency encoded by converting serial input data of the optical signals into parallel data in a bit-by-bit decomposition, each bit being converted to a particular frequency, the frequencies of the converted bits being shuffled into non-sequential order;

wherein optical communication is enabled among the modules via the optical communication fiber, and

wherein optical communication of individual data streams formatted according to a first communication protocol of the plurality of different communication protocols is distinguished from optical communication of individual data streams formatted according to a second communication protocol of the plurality of different communication protocols using intensity modulation of the optical signals.

2. The system of claim 1, wherein the optical communication fiber is a polymer optical fiber.

3. The system of claim 1, wherein the optical communication fiber comprises a section of a glass optical fiber and a section of a polymer optical fiber.

4. The system of claim 1, wherein the individual data streams each have a different wavelength and are multiplexed on the optical communication fiber using wavelength division multiplexing.

5. The system of claim 1, wherein the individual data streams communicate information according to a category of information selected from the group of categories consisting of safety information, security information, control command information, and sensor measurement information.

6. The system of claim 1, wherein the system further comprises a wavelength selective device for permitting propagation on the optical communication fiber of a first optical signal having a first wavelength and for blocking propagation on the optical communication fiber of a second optical signal having a second wavelength different from the first wavelength.

7. The system of claim 6, wherein the first optical signal is associated with a first category of information and the second optical signal is associated with a second category of information.

8. The system of claim 7, wherein the categories of information are selected from the group of categories consisting of safety information, security information, control command information, and sensor measurement information.

9. The system of claim 1, wherein the individual data streams are multiplexed on the optical communication fiber using at least one of the following:

wavelength division multiplexing, frequency division multiplexing, and time division multiplexing.

10. The system of claim 1, wherein each of the modules comprises a processor, said processor being configured for executing a control application to control one or more process control devices in an industrial plant.

11. The system of claim 10, wherein the optical signals include a first optical signal having a first wavelength and a second optical signal having a second wavelength different from the first wavelength, and wherein the first optical signal is associated with a higher priority message and the second optical signal is associated with a lower priority message.

12. The system of claim 1, further comprising for each of the modules a cladding on the optical communication fiber opposite the corresponding drop to improve coupling between each of the modules and the optical communication fiber.

13. The system of claim 12, wherein the cladding comprises a reflective material.

14. The system of claim 1, wherein the drop corresponding to each of the modules comprises a separator and one or more optical detectors, said separator being configured to separate light on the optical communication fiber into the optical signals representing the individual data streams and said optical detectors being configured to convert the separated optical signals into electrical signals.

15. The system of claim 14, wherein the drop further comprises one or more emitters, each of said emitters being tuned to emit at a different wavelength.

16. An optical communication system comprising:

a polymer optical fiber;

a first module comprising a first optical transceiver, wherein the first module transmits a first optical signal on the polymer optical fiber, said first optical signal having a first wavelength and formatted according to a first communication protocol; and

a second module comprising a second optical transceiver, wherein the second module transmits a second optical signal on the polymer optical fiber, said second optical signal having a second wavelength and formatted according to a second communication protocol, wherein the second wavelength is different from the first wavelength and the second communication protocol is different from the first communication protocol, and wherein the second optical signal is distinguished from the first optical signal using intensity modulation;

wherein the first and second optical signals are frequency encoded by converting serial input data of the first and second optical signals into parallel data in a bit-by-bit decomposition, each bit being converted to a particular frequency, the frequencies of the converted bits being shuffled into non-sequential order.

17. The system of claim 16, further comprising a third module comprising a third optical transceiver, wherein the third module is coupled to the polymer optical fiber.

18. The system of claim 17, wherein the first module is coupled to the polymer optical fiber by a drop.

19. The system of claim 18, wherein the drop comprises an emitter component that introduces the first optical signal into the polymer optical fiber and wherein reflective material is disposed on the outside of the polymer optical fiber at a position opposed to the drop.

20. The system of claim 18, wherein the drop comprises:

a separator component that separates optical signals propagating on the drop based on wavelength; and

a plurality of detectors, each detector physically aligned to detect an optical signal separated by the separator component.

21. The system of claim 16, further comprising an equipment cabinet, wherein the first module and the second module and the polymer optical fiber are retained within the equipment cabinet.

22. A method of communication comprising:

transmitting a first optical signal on a first polymer optical fiber, wherein the first optical signal has a first wavelength and a first communication protocol format, and wherein the first wavelength is allocated for a first category of communication;

transmitting a second optical signal on the first polymer optical fiber, wherein the second optical signal has a second wavelength different from the first wavelength and a second communication protocol format different from the first communication protocol format, and wherein the second wavelength is allocated for a second category of communication;

separating the first optical signal from the second optical signal based on a difference in wavelength and communication protocol format;

after separating the first optical signal from the second optical signal, receiving the first optical signal;

frequency encrypting the optical signals by converting serial input data of the optical signals into parallel data in a bit-by-bit decomposition;

converting each bit to a particular frequency; and

shuffling the frequencies of the converted bits into non-sequential order.

23. The method of claim 22, further comprising, after separating the first optical signal, receiving the second optical signal.

24. The method of claim 23, wherein the receiving the first optical signal and receiving the second optical signal is based at least in part on differentiating between the first category of communication and the second category of communication.

25. The method of claim 24, further comprising processing the information received from the first optical signal before processing the information received from the second optical signal based on a higher priority associated with the first category of communication relative to a lower priority associated with the second category of communication.

26. The method of claim 22, wherein separating the first optical signal from the second optical signal is performed by a diffraction grating.

27. The method of claim 22, wherein separating the first optical signal from the second optical signal is performed by a prism.

28. The method of claim 22, wherein separating the first optical signal from the second optical signal is performed by a wavelength selective filter and further comprising propagating the first optical signal on a second polymer optical fiber, wherein the second polymer optical fiber is coupled to the first polymer optical fiber by the wavelength selective filter.

29. An optical communication system comprising:

a polymer optical fiber;

a plurality of optical transceivers, each of said optical transceivers being configured for transmitting and/or receiving one or more optical signals via the optical fiber, said optical signals comprising frequency encoded data and representing a plurality of individual data streams each formatted according to a different communication protocol, wherein the different communication protocols are distinguished from each other by intensity modulation of the optical signals, wherein the optical signals are frequency encoded by converting serial input data of the optical signals into parallel data in a bit-by-bit decomposition, each bit being converted to a particular frequency, the frequencies of the converted bits being shuffled into non-sequential order;

a plurality of optical drops for coupling the optical transceivers to the optical fiber, each of said optical drops corresponding to one of the optical transceivers; and

a plurality of processors, each of said processors being configured for executing a control application to control one or more process control devices in an industrial plant and corresponding to one of the optical transceivers;

wherein optical communication is enabled among the process control devices via the optical fiber.