COUPLING OPTICAL SIGNALS INTO SILICON OPTOELECTRONIC CHIPS

• US 20170285263A1
• Filed: 06/20/2017
• Published: 10/05/2017
• Est. Priority Date: 11/06/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Luxtera Incorporated (Cisco Systems, Inc.)
• Inventors: Pinguet, Thierry, Mekis, Attila, Gloeckner, Steffen
• Granted Patent: US 9,904,012 B2
• Time in Patent Office: Days
• CPC Class Codes: G01J 1/02 Details
• CPC Class Codes: G01J 1/0425 using optical fibers
• CPC Class Codes: G02B 2006/12038 Glass (SiO2 based materials)
• CPC Class Codes: G02B 2006/12061 Silicon
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• CPC Class Codes: G02B 2006/12157 Isolator
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/4208 using non-reciprocal elements or birefringent plates, i.e. quasi-isolators optical isolators per se G02F1/093, G02F1/0955

Abstract

A method and system for coupling optical signals into silicon optoelectronic chips are disclosed and may include coupling one or more optical signals into a back surface of a CMOS photonic chip comprising photonic, electronic, and optoelectronic devices. The devices may be integrated in a front surface of the chip and one or more optical couplers may receive the optical signals in the front surface of the chip. The optical signals may be coupled into the back surface of the chip via one or more optical fibers and/or optical source assemblies. The optical signals may be coupled to the grating couplers via a light path etched in the chip, which may be refilled with silicon dioxide. The chip may be flip-chip bonded to a packaging substrate. Optical signals may be reflected back to the grating couplers via metal reflectors, which may be integrated in dielectric layers on the chip.

Claims

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

in a photonic receiver comprising a silicon photonic chip bonded to a substrate, coupling one or more optical signals into a back surface of said silicon photonic chip through a light path in a region where silicon is removed from said silicon photonic chip, wherein photonic devices are integrated in said silicon photonic chip and said one or more optical signals are received by one or more optical couplers at said front surface of said silicon photonic chip.

2. The method according to claim 1, comprising coupling said one or more optical signals into said back surface of said silicon photonic chip via one or more optical fibers.

3. The method according to claim 1, wherein said optical couplers comprise grating couplers.

4. The method according to claim 1, wherein said silicon photonic chip comprises an optical transmitter that receives an optical source signal via said back surface of said silicon photonic chip from an optical source assembly bonded to said silicon photonic chip.

5. The method according to claim 1, comprising coupling said one or more optical signals to said one or more grating couplers via an anti-reflective coating on said back surface of said silicon photonic chip.

6. The method according to claim 5, wherein said region where silicon is removed from said silicon photonic chip comprises silicon dioxide.

7. The method according to claim 1, wherein said front surface of said silicon photonic chip is bonded to a second chip.

8. The method according to claim 1, comprising reflecting optical signals that pass through said one or more optical couplers back to said one or more optical couplers via one or more metal reflectors.

9. The method according to claim 8, wherein said one or more metal reflectors are integrated in dielectric layers on said silicon photonic chip.

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

a photonic receiver comprising a silicon photonic chip bonded to a die, said silicon photonic chip having photonic devices integrated in said silicon photonic chip and a light path in a region where silicon is removed from a back surface of said silicon photonic chip, wherein one or more optical signals are coupled into said back surface of said silicon photonic chip via said light path, and one or more optical couplers at said front surface of said silicon photonic chip are operable to receive said one or more optical signals.

11. The system according to claim 10, wherein said one or more optical signals are coupled into said back surface of said silicon photonic chip via one or more optical fibers coupled to said light path.

12. The system according to claim 11, wherein said light path passes through a buried oxide layer in said silicon photonic chip.

13. The system according to claim 10, wherein said optical couplers comprise grating couplers.

14. The system according to claim 10, wherein an optical source signal for an optical transmitter in said silicon photonic chip is coupled into said back surface of said silicon photonic chip from an optical source assembly.

15. The system according to claim 10, wherein said one or more optical signals is coupled to said optical couplers through an anti-reflection coating on said back surface of said silicon photonic chip.

16. The system according to claim 15, wherein said region where silicon is removed from said silicon photonic chip comprises silicon dioxide.

17. The system according to claim 10, wherein said front surface of said silicon photonic chip is bonded to a second chip.

18. The system according to claim 10, wherein said photonic devices are operable to reflect optical signals that pass through said one or more grating couplers back to said one or more grating couplers via one or more metal reflectors.

19. The system according to claim 18, wherein said one or more metal reflectors are integrated in dielectric layers on said silicon photonic chip.

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

a photonic receiver comprising a silicon photonic chip with photonic devices integrated beneath a stack of dielectric layers in said silicon photonic chip, wherein said silicon photonic chip is bonded to a second chip; and

wherein one or more optical couplers integrated beneath a metal reflector embedded in said dielectric layers receive one or more optical signals coupled into a back surface of said silicon photonic chip through a region where silicon is removed from said silicon photonics chip.