Method and system for implementing high-speed electrical interfaces between semiconductor dies in optical communication systems

• US 10,061,094 B2
• Filed: 09/26/2017
• Issued: 08/28/2018
• Est. Priority Date: 02/23/2010
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Luxtera Incorporated (Cisco Systems, Inc.)
• Inventors: Kucharski, Daniel, Guckenberger, John Andrew, Pinguet, Thierry, Abdalla, Sherif
• Primary Examiner(s): Misiura, Brian T
• Application Number:
  US15/716,103
• Publication Number:
  US 20180017747A1
• Time in Patent Office: 336 Days
• Field of Search: 710105
• CPC Class Codes: G02B 6/4274 Electrical aspects G02B6/4263 and G02B6/4265 take precedence
• CPC Class Codes: G02B 6/4286 Optical modules with optical power monitoring

Abstract

A method and system for implementing high-speed electrical interfaces between semiconductor dies in optical communication systems are disclosed and may include communicating electrical signals between a first die and a second die via coupling pads which may be located in low impedance points in Tx and Rx paths. The electrical signals may be communicated via one or more current-mode, controlled impedance, and/or capacitively-coupled interfaces. The current-mode interface may include a cascode amplifier stage split between source and drain terminals of transistors on the dies. The controlled-impedance interfaces may include transmission line drivers on a first die and transmission lines on a second die. The capacitively-coupled interfaces may include capacitors formed by contact pads on the dies. The coupling pads may be connected via one or more of: wire bonds, metal pillars, solder balls, or conductive resin. The dies may comprise CMOS and may be coupled in a flip-chip configuration.

Claims

1. A method for processing signals, the method comprising:

in a communication system, communicating electrical signals between a first die and a second die via coupling pads on said first die and said second die, wherein said coupling pads are located at low impedance points between two cascode transistors in one or more transmit paths and/or one or more receive paths in said communication system, wherein a first of said two cascode transistors is integrated in said first die and a second of said two cascode transistors is integrated in said second die.

2. The method according to claim 1, comprising communicating said electrical signals via one or more current-mode interfaces.

3. The method according to claim 2, wherein said one or more current-mode interfaces comprise a cascode amplifier stage split between a source terminal of said first of said two cascode transistors integrated in said first die and a drain terminal of said second of said two cascode transistors integrated in said second die.

4. The method according to claim 2, wherein said one or more current-mode interfaces comprise a cascode amplifier stage split between a source terminal of said first of said two cascode transistors integrated in said second die and a drain terminal of said second of said two cascode transistors integrated in-said first die.

5. The method according to claim 1, comprising communicating said electrical signals via one or more controlled-impedance interfaces.

6. The method according to claim 5, wherein said one or more controlled-impedance interfaces comprise one or more transmission line drivers on said first die and one or more transmission lines on said second die of said communication system.

7. The method according to claim 1, comprising communicating said electrical signals via one or more capacitively-coupled interfaces.

8. The method according to claim 7, wherein said capacitively-coupled interfaces comprise capacitors formed by one or more of said contact pads on said first die and one or more of said contact pads on said second die.

9. The method according to claim 1, comprising communicating said electrical signals via one or more inductively-coupled interfaces.

10. The method according to claim 1, wherein said coupling pads are connected via one or more of:

wire bonds, metal pillars, solder balls, or conductive resin.

11. The method according to claim 1, wherein said first die and said second die are coupled in a flip-chip configuration.

12. The method according to claim 1, wherein said first die comprises a complimentary metal-oxide-semiconductor (CMOS) die.

13. The method according to claim 1, wherein said second die comprises an optoelectronics die.

14. A system for processing signals, the system comprising:

a communication system comprising a first die and a second die, said first die and said second die comprising circuitry that is operable to communicate electrical signals between said first die and said second die via coupling pads on said first die and said second die, wherein said coupling pads are located at low impedance points between two cascode transistors in one or more transmit paths and/or one or more receive paths in said communication system, wherein a first of said two cascode transistors is integrated in said first die and a second of said two cascode transistors is integrated in said second die.

15. The system according to claim 14, wherein said circuitry is operable to communicate said electrical signals via one or more current-mode interfaces.

16. The system according to claim 15, wherein said one or more current-mode interfaces comprise a cascode amplifier stage split between a source terminal of said first of said two cascode transistors integrated in said first die and a drain terminal of said second of said two cascode transistors integrated in said second die.

17. The system according to claim 15, wherein said one or more current-mode interfaces comprise a cascode amplifier stage split between a source terminal of said first of said two cascode transistors integrated in said second die and a drain terminal of said second of said two cascode transistors integrated in said first die.

18. The system according to claim 14, wherein said circuitry is operable to communicate said electrical signals via one or more controlled-impedance interfaces.

19. The system according to claim 18, wherein said one or more controlled-impedance interfaces comprise one or more transmission line drivers on said first die and one or more transmission lines on said second die of said communication system.

20. The system according to claim 14, wherein said circuitry is operable to communicate said electrical signals via one or more capacitively-coupled interfaces.

21. The system according to claim 20, wherein said capacitively-coupled interfaces comprise capacitors formed by one or more of said contact pads on said first die and one or more of said contact pads on said second die.

22. The system according to claim 14, wherein said circuitry is operable to communicate said electrical signals via one or more inductively-coupled interfaces.

23. The system according to claim 14, wherein said coupling pads are connected via one or more of:

wire bonds, metal pillars, solder balls, or conductive resin.

24. The system according to claim 14, wherein said first die and said second die are coupled in a flip-chip configuration.

25. The system according to claim 14, wherein said first die comprises an electronics complimentary metal-oxide-semiconductor (CMOS) die.

26. The system according to claim 14, wherein said second die comprises an optoelectronics CMOS die.