Optical junction apparatus and methods employing optical power transverse-transfer

• US 20070110369A1
• Filed: 01/16/2007
• Published: 05/17/2007
• Est. Priority Date: 10/30/2001
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Xponent Photonics, Inc. (Hoya Corporation)
• Inventors: Blauvelt, Henry, Vernooy, David, Paslaski, Joel, Vahala, Kerry
• Granted Patent: US 7,379,638 B2
• Time in Patent Office: Days
• US Class Current: 385/50
• CPC Class Codes: G02B 2006/12119 Bend
• CPC Class Codes: G02B 2006/12195 Tapering
• CPC Class Codes: G02B 6/12002 Three-dimensional structures
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/125 Bends, branchings or intersections
• CPC Class Codes: G02B 6/2804 forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
• CPC Class Codes: G02B 6/2821 using lateral coupling between contiguous fibres to split or combine optical signals
• CPC Class Codes: G02B 6/2852 using tapping light guides arranged sidewardly, e.g. in a non-parallel relationship with respect to the bus light guides (light extraction or launching through cladding, with or without surface discontinuities, bent structures)
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide
• CPC Class Codes: G02B 6/42 Coupling light guides with opto-electronic elements
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 6/423 using guiding surfaces for the alignment
• CPC Class Codes: G02B 6/4232 using the surface tension of fluid solder to align the elements, e.g. solder bump techniques flip-chip mounting techniques in assembly of semiconductor devices H01L24/81
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An optical apparatus comprises an optical device fabricated on a substrate, an external-transfer optical waveguide fabricated on the substrate and/or on the optical device, and a transmission optical waveguide. The optical device and/or the external-transfer waveguide are adapted for and positioned for transfer of optical power therebetween (end-transfer or transverse-transfer). The external-transfer waveguide and/or the transmission waveguide are adapted for transverse-transfer of optical power therebetween (mode-interference-coupled or adiabatic). The transmission waveguide is initially provided as a component mechanically separate from the substrate, device, and external-transfer waveguide. Assembly of the transmission waveguide with the substrate, device, and/or external-transfer waveguide results in relative positioning of the external-transfer waveguide and the transmission waveguide for enabling transverse-transfer of optical power therebetween. Optical power transfer between the device and the transmission waveguide through the external-transfer waveguide is thereby enabled. The transmission waveguide may preferably comprise a planar waveguide on a waveguide substrate.

Claims

1. A method comprising:

(a) transferring an optical signal between an optical device of an optical device subunit and an external transfer planar optical waveguide of the optical device subunit, the optical device subunit comprising a device substrate, the optical device formed on the device substrate, and the external-transfer planar optical waveguide formed over the device substrate, the external-transfer planar optical waveguide being integrated with the optical device for enabling transfer of optical power between the optical device and the external-transfer planar optical waveguide, the optical signal propagating in the external-transfer optical waveguide; and

(b) transferring the optical signal between the external-transfer planar optical waveguide and a transmission optical waveguide of an optical transmission subunit, the external-transfer planar optical waveguide and the transmission optical waveguide each having a respective optical junction region thereof, the external-transfer planar optical waveguide or the transmission optical waveguide being adapted for enabling transverse-transfer of optical power between the optical waveguides at the respective optical junction regions, the optical device subunit and the optical transmission subunit comprising discrete subunits assembled together.

2. The method of claim 1 wherein the external-transfer planar optical waveguide is formed on the device substrate or on the optical device.

3. The method of claim 1 wherein the optical device subunit or the optical transmission subunit is structurally adapted for assembly of the optical transmission subunit with the optical device subunit.

4. The method of claim 1 wherein the optical device subunit or the optical transmission subunit is structurally adapted for positioning the respective optical junction regions for enabling transverse-transfer of optical power between the optical waveguides.

5. The method of claim 1 wherein the transmission optical waveguide or the external-transfer planar optical waveguide is adapted for enabling mode-interference-coupled transverse-transfer of optical power between the optical waveguides at the respective optical junction regions.

6. The method of claim 1 wherein the transmission optical waveguide or the external-transfer planar optical waveguide is adapted for enabling substantially adiabatic transverse-transfer of optical power between the optical waveguides at the respective optical junction regions.

7. The method of claim 6 wherein the transmission optical waveguide or the external-transfer planar optical waveguide is adapted for maintaining transverse-offset optical power transfer loss therebetween less than about 0.5 dB for relative transverse offsets of the optical waveguides less than about ±

1.0 times a corresponding transverse optical mode size characteristic of the optical waveguides.

8. The method of claim 6 wherein the transmission optical waveguide or the external-transfer optical waveguide is adapted for maintaining transverse-offset optical power transfer loss therebetween within about ±

0.5 dB of a nominal optical power transfer loss level for relative transverse offsets of the optical waveguides less than about ±

1.0 times a corresponding transverse optical mode size characteristic of the optical waveguides.

9. The method of claim 1 wherein the optical device or the external-transfer planar optical waveguide is adapted for and positioned for enabling end-transfer of optical power between the optical device and the external-transfer planar optical waveguide.

10. The method of claim 1 wherein the optical device or the external-transfer planar optical waveguide is adapted for and positioned for enabling transverse-transfer of optical power between the optical device and the external-transfer optical waveguide.

11. The method of claim 1 wherein the external-transfer planar optical waveguide comprises a low-modal-index optical waveguide.

12. The method of claim 11 wherein the optical device comprises a high-index semiconductor device.

13. The method of claim 1 wherein the transmission optical waveguide comprises a low-modal-index optical waveguide.

14. The method of claim 1 wherein the optical transmission subunit comprises a transmission planar optical waveguide formed on a waveguide substrate.

15. The method of claim 14 wherein the transmission optical waveguide is adapted at a distal end thereof for enabling end-transfer of optical power between the transmission optical waveguide and an optical fiber.

16. An method comprising:

(a) transferring an optical signal between an optical device of an optical device subunit and an external transfer planar optical waveguide of the optical device subunit, the optical device subunit comprising a device substrate, the optical device formed on the device substrate, and the external-transfer planar optical waveguide formed over the device substrate, the external-transfer planar optical waveguide being integrated with the optical device for enabling transfer of optical power between the optical device and the external-transfer planar optical waveguide, the optical signal propagating in the external-transfer optical waveguide; and

(b) transferring the optical signal between the external-transfer planar optical waveguide and a transmission optical waveguide of an optical transmission subunit, the external-transfer planar optical waveguide and the transmission optical waveguide each having a respective optical junction region thereof, the external-transfer planar optical waveguide or the transmission optical waveguide including means for enabling transverse-transfer of optical power between the optical waveguides at the respective optical junction regions, the optical device subunit and the optical transmission subunit comprising discrete subunits assembled together.

17. The method of claim 16 wherein the optical device subunit or the optical transmission subunit includes means for assembling the optical transmission subunit with the optical device subunit.

18. The method of claim 16 wherein the optical device subunit or the optical transmission subunit includes means for positioning the transmission optical waveguide and the external-transfer planar optical waveguide for enabling transverse-transfer of optical power therebetween.

19. A method comprising transferring an optical signal between an optical device of an optical device subunit and an external transfer planar optical waveguide of the optical device subunit, the optical device subunit comprising a device substrate, the optical device formed on the device substrate, and the external-transfer planar optical waveguide formed over the device substrate, the external-transfer planar optical waveguide being integrated with the optical device for enabling transfer of optical power between the optical device and the external-transfer planar optical waveguide, the optical signal propagating in the external-transfer optical waveguide, the external-transfer planar optical waveguide being adapted for enabling transverse-transfer of optical power at an optical junction region thereof between the external-transfer optical waveguide and a transmission optical waveguide of an optical transmission subunit, the optical device subunit comprising a discrete subunit relative to the optical transmission subunit.

20. The method of claim 19 wherein the external-transfer planar optical waveguide is formed on the device substrate or on the optical device.

21. The method of claim 19 wherein the optical device subunit is structurally adapted for assembly with the optical transmission subunit.

22. The method of claim 19 wherein the optical device subunit is structurally adapted for positioning the optical junction region and the transmission optical waveguide for enabling transverse-transfer of optical power between the optical waveguides.

23. The method of claim 19 wherein the external-transfer planar optical waveguide is adapted for enabling substantially adiabatic transverse-transfer of optical power between the external-transfer planar optical waveguide and another optical waveguide at the optical junction region.

24. The method of claim 23 wherein at least a portion of the external-transfer planar optical waveguide comprises a core and lower-index cladding, and at least one transverse dimension of the core or the cladding varies longitudinally along at least a portion of the optical junction region.

25. The method of claim 23 wherein at least a portion of the external-transfer planar optical waveguide comprises a core and lower-index cladding, and a refractive index of the core or the cladding varies longitudinally along at least a portion of the optical junction region.

26. The method of claim 19 wherein the external-transfer planar optical waveguide is adapted for enabling mode-interference-coupled transverse-transfer of optical power between the external-transfer planar optical waveguide and another optical waveguide at the optical junction region.

27. The method of claim 19 wherein the optical device or the external-transfer planar optical waveguide is adapted for and positioned for enabling end-transfer of optical power between the optical device and the external-transfer planar optical waveguide.

28. The method of claim 19 wherein the optical device or the external-transfer planar optical waveguide is adapted for and positioned for enabling transverse-transfer of optical power between the optical device and the external-transfer planar optical waveguide.

29. The method of claim 19 wherein the external-transfer planar optical waveguide comprises a low-modal-index optical waveguide.

30. The method of claim 29 wherein the optical device comprises a high-index semiconductor device.

31. The method of claim 29 wherein the external-transfer planar optical waveguide comprises a silica-based optical waveguide.

32. The method of claim 31 wherein:

the external-transfer planar optical waveguide comprises a core and lower-index cladding;

the core comprises silicon nitride, silicon oxynitride, or doped silica; and

the cladding comprises silica or doped silica.

33. The method of claim 19 wherein the optical device comprises a laser, a modulator, or a photodetector.

34. The method of claim 19 wherein the optical device comprises a high-index semiconductor device.

35. The method of claim 19 wherein the optical device comprises a III-V semiconductor device.

36. The method of claim 19 wherein at least a portion of the external-transfer planar optical waveguide is adapted for providing a portion of functionality of the optical device.

37. The method of claim 36 wherein at least a portion of the external-transfer planar optical waveguide is adapted for providing at least a portion of wavelength-dependent functionality of the optical device.

38. A method comprising transferring an optical signal between an optical device of an optical device subunit and an external transfer planar optical waveguide of the optical device subunit, the optical device subunit comprising a device substrate, the optical device formed on the device substrate, and the external-transfer planar optical waveguide formed over the device substrate, the external-transfer planar optical waveguide being integrated with the optical device for enabling transfer of optical power between the optical device and the external-transfer planar optical waveguide, the optical signal propagating in the external-transfer optical waveguide, the external-transfer planar optical waveguide including means for enabling transverse-transfer of optical power at an optical junction region thereof between the external-transfer optical waveguide and a transmission optical waveguide of an optical transmission subunit, the optical device subunit comprising a discrete subunit relative to the optical transmission subunit.

39. The method of claim 38 wherein the optical device subunit includes means for assembling the optical transmission subunit with the optical device subunit.

40. The method of claim 38 wherein the optical device subunit includes means for positioning the transmission optical waveguide and the external-transfer planar optical waveguide for enabling transverse-transfer of optical power therebetween.