System and method for multiple bit optical data transmission in memory systems

• US 7,254,331 B2
• Filed: 08/09/2002
• Issued: 08/07/2007
• Est. Priority Date: 08/09/2002
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Murphy, Tim
• Primary Examiner(s): Bello; Agustin
• Application Number:
  US10/215,505
• Publication Number:
  US 20040028412A1
• Time in Patent Office: 1,824 Days
• Field of Search: 398/70, 398/42, 370/281, 370/295
• US Class Current: 398/70
• CPC Class Codes: H04B 10/801 using optical interconnects, e.g. light coupled isolators, circuit board interconnections

Abstract

The disclosed system and method data increases data transmission speed through a memory system by using optical signals comprising a plurality of wavelengths of light so that each pulse of optical signals can represent more than a single bit of data. An optical transmitter comprises multiple, separately controllable light-emitting sections which generate light at different wavelengths. A photoreceptor, comprising sections of materials responsive to light received at different wavelengths, provides an output signal corresponding to the light signals received at the different wavelengths. The photoreceptor therefore can decode the received optical signals into a multiple bit output sequence corresponding with the multiple bit sequence originally transmitted. The disclosed method and system can be used to communicate signals between a plurality of memory devices and a memory hub within a memory module or directly to a system memory controller, and/or between a plurality of memory hubs and a system memory controller.

Claims

1. A memory hub for selectively communicating data between a system and a plurality of associated system memory devices communicably coupled with the memory hub, the memory hub comprising:

a hub control unit, the hub control unit receiving incoming control signals, address signals, and data write signals and operable to route a memory control signal, a memory address signal, and a memory data write signal to at least one of the associated memory devices based on the contents of the control signal, the address signal, and the data signal, the memory transceiver being further operable to receive data read signals from the associated memory devices and relay the data read information to the system, and

a multiple bit optical transceiver coupled with the hub control unit, the multiple but optical transceiver comprising;

a light emitting device comprising;

a plurality of light emitting diodes subsisting on a common bond pad each of the light emitting diodes operable to generate light in a particular range of wavelengths upon being electrically stimulated;

the multiple bit optical transceiver operable to communicate multiple bit optical signals comprising a plurality of wavelengths of light, combinations of the plurality of wavelengths of light representing a combination of data bits in each transmission pulse, the multiple bit optical transceiver further operable to decode an incoming multiple bit optical signal into incoming electrical signals understandable by the hub control unit, and further operable to encode outgoing electrical signals into an outgoing multiple bit optical signal.

2. The system of claim 1 wherein a number of possible data sequences that can be signified by the optical transceiver is equal to two to the power of a number of the light emitting diodes.

3. The memory hub of claim 1 wherein the multiple bit optical transceiver comprises a photoreceptor comprising a plurality of light sensitive materials each of which generates an electrical current upon receiving light of a particular range of wavelengths.

4. The memory hub of claim 3 wherein a number of possible data sequences that can be distinguished by the photoreceptor is equal to two to the power of the plurality of light sensitive materials.

5. The memory hub of claim 1 wherein the wavelengths are within a visible spectrum of light.

6. The memory hub of claim 1 wherein the wavelengths are outside a visible spectrum of light.

7. The memory hub of claim 1 further comprising an optical medium coupled to the multiple bit optical transceiver, wherein the multiple bit optical transmission signal generated is communicated through the optical medium.

8. The memory hub of claim 7 wherein the optical transmission medium is a free space medium.

9. The memory hub of claim 1 wherein the optical transmission medium is a reflective medium.

10. The memory hub of claim 1 wherein the optical transmission medium is a fiber optic medium.

11. A system comprising a plurality of memory devices arranged on a memory module substrate having an embedded fiber optic matrix through which each of the memory devices is optically coupled to the memory hub of claim 1.

12. A memory module, comprising:

an insulative substrate;

an optical memory hub mounted on the substrate, the optical memory hub having a primary optical transceiver operable to transmit a multiple bit optical control signal comprising a plurality of wavelengths of light, each combination of wavelengths of light representing a data sequence comprising a plurality of control signals, data signals, and address signals, the primary optical transceiver further being operable to receive optical data signals, the primary optical transceiver comprising;

a light emitting device comprising;

a plurality of light emitting diodes each of which is operable to generate light in a particular range of wavelengths upon being electrically stimulated, the light emitting diodes subsisting on a common bond pad;

a plurality of optical memory devices mounted on the substrate, each of the optical memory devices having a secondary optical transceiver operable to receive the multiple bit optical control signal, and transmit optical data signals; and

an optical transmission medium operable to optically couple the primary optical transceiver of the optical memory hub and the secondary optical transceiver of each of the plurality of optical memory devices.

13. The memory module of claim 12 wherein a number of possible data sequences that can be signified by the primary optical transceiver is equal to two to the power of a number of the light emitting diodes.

14. The memory module of claim 12 wherein the primary optical transceiver comprises a photoreceptor comprising a plurality of light sensitive materials each of which generates an electrical current upon receiving light of a particular range of wavelengths.

15. The memory module of claim 14 wherein a number of possible data sequences that can be distinguished by the photoreceptor is equal to two to the power of the plurality of light sensitive materials.

16. The memory module of claim 12 wherein the wavelengths are within a visible spectrum of light.

17. The memory module of claim 12 wherein the wavelengths are outside a visible spectrum of light.

18. The memory module of claim 12 wherein the optical transmission medium is a free space medium.

19. The memory module of claim 12 wherein the optical transmission medium is a reflective medium.

20. The memory module of claim 12 wherein the optical transmission medium is a fiber optic medium.

21. The memory module of claim 12 wherein the substrate comprises an embedded fiber optic matrix through which each of the memory devices is optically coupled to the memory hub.

22. A computer system, comprising:

a processor;

an input device, operably connected to the processor, allowing data to be entered into the computer system;

an output device, operably connected to the processor, allowing data to be output from the computer system; and

a system memory operably connected to the processor and receiving memory control signals from the processor, the system memory comprising a plurality of memory modules, each of the memory modules comprising;

an insulative substrate;

an optical memory hub mounted on the substrate, the optical memory hub having a primary optical transceiver operable to transmit a multiple bit optical control signal comprising a plurality of wavelengths of light, each combination of wavelengths of light representing a data sequence comprising a plurality of control signals, data signals, and address signals, the primary optical transceiver further being operable to receive optical data signals, the primary optical transceiver comprising;

a light emitting device comprising;

a plurality of light emitting diodes each of which is operable to generate light in a particular range of wavelengths upon being electrically stimulated, the light emitting diodes subsisting on a common bond pad; and

a plurality of optical memory devices mounted on the substrate, each of the optical memory devices having a secondary optical transceiver operable to receive the multiple bit optical control signal, and transmit optical data signals;

an optical transmission medium operable to optically couple the primary optical transceiver of the optical memory hub and the secondary optical transceiver of each of the plurality of optical memory devices.

23. The system of claim 22 wherein a number of possible data sequences that can be signified by the primary optical transceiver is equal to two to the power of a number of the light emitting elements.

24. The system of claim 22 wherein the primary optical transceiver comprises a photoreceptor comprising a plurality of light sensitive materials each of which generates an electrical current upon receiving light of a particular range of wavelengths.

25. The system of claim 24 wherein a number of possible data sequences that can be distinguished by the photoreceptor is equal to two to the power of the plurality of light sensitive materials.

26. The system of claim 22 wherein the wavelengths are within a visible spectrum of light.

27. The system of claim 22 wherein the wavelengths are outside a visible spectrum of light.

28. The system of claim 22 wherein the optical transmission medium is a free space medium.

29. The system of claim 22 wherein the optical transmission medium is a reflective medium.

30. The system of claim 22 wherein the optical transmission medium is a fiber optic medium.

31. The system of claim 22 wherein the substrate comprises an embedded fiber optic matrix through which each of the memory devices is optically coupled to the memory hub.

32. A computer system, comprising:

a processor;

an input device, operably connected to the processor, allowing data to be entered into the computer system;

an output device, operably connected to the processor, allowing data to be output from the computer system; and

a system memory operably connected to the processor and receiving memory control signals from the processor, the system memory comprising;

an optical memory controller, the optical memory controller having a primary optical transceiver operable to transmit a multiple bit optical control signal comprising a plurality of wavelengths of light, each combination of wavelengths of light representing a data sequence comprising a plurality of control signals, data signals, and address signals, the primary optical transceiver being further operable to receive optical data signals, the primary optical transceiver comprising;

a light emitting device comprising a plurality of light emitting diodes each of which is operable to generate light in a particular range of wavelengths upon being electrically stimulated, the light emitting diodes subsisting on a common bond pad;

a plurality of optical memory devices mounted on the substrate, each of the optical memory devices having a secondary optical transceiver operable to receive the multiple bit optical control signal, and transmit optical data signals; and

an optical transmission medium operable to optically couple the primary optical transceiver of the optical memory controller and the secondary optical transceiver of each of the plurality of optical memory devices.

33. The system of claim 32 wherein a number of possible data sequences that can be signified by the primary optical transceiver is equal to two to the power of a number of the light emitting diodes.

34. The system of claim 32 wherein the primary optical transceiver comprises a photoreceptor comprising a plurality of light sensitive materials each of which generates an electrical current upon receiving light of a particular range of wavelengths.

35. The system of claim 34 wherein a number of possible data sequences that can be distinguished by the photoreceptor is equal to two to the power of the plurality of light sensitive materials.

36. The system of claim 32 wherein the wavelengths are within a visible spectrum of light.

37. The system of claim 32 wherein the wavelengths are outside a visible spectrum of light.

38. The system of claim 32 wherein the optical transmission medium is a free space medium.

39. The system of claim 32 wherein the optical transmission medium is a reflective medium.

40. The system of claim 32 wherein the optical transmission medium is a fiber optic medium.

41. The system of claim 32 wherein the optical transmission medium is fiber optic matrix embedded in a computer system circuit board through which each of the memory devices is optically coupled to the optical memory controller.