Edge coupling device fabrication

• US 9,703,039 B2
• Filed: 04/07/2015
• Issued: 07/11/2017
• Est. Priority Date: 04/09/2014
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Liu, Zongrong, Pan, Huapu, Wei, Hongzhen, Chen, Hongmin
• Primary Examiner(s): Doan, Jennifer
• Application Number:
  US14/680,917
• Publication Number:
  US 20150293303A1
• Time in Patent Office: 826 Days
• CPC Class Codes: G02B 2006/12061 Silicon
• CPC Class Codes: G02B 2006/12097 Ridge, rib or the like
• CPC Class Codes: G02B 2006/12195 Tapering
• CPC Class Codes: G02B 6/1223 high refractive index type, i.e. high-contrast waveguides
• CPC Class Codes: G02B 6/132 by deposition of thin films
• CPC Class Codes: G02B 6/136 by etching
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide

Abstract

A method of fabricating an edge coupling device and an edge coupling device are provided. The method includes removing a portion of cladding material to form a trench over an inversely tapered silicon waveguide, depositing a material having a refractive index greater than silicon dioxide over remaining portions of the cladding material and in the trench, and removing a portion of the material within the trench to form a ridge waveguide.

Claims

1. A method of fabricating an edge coupling device, comprising:

removing a portion of cladding material to form a trench over an inversely tapered silicon waveguide;

depositing a material having a refractive index greater than silicon dioxide over remaining portions of the cladding material and in the trench; and

removing a portion of the material within the trench to form a ridge waveguide within the trench.

2. The method of claim 1, further comprising forming an etch stop layer over the inversely tapered silicon waveguide prior to removing the portion of the cladding material, and wherein the portion of the cladding material is removed by etching down to the etch stop layer.

3. The method of claim 2, further comprising removing the portion of the cladding material using a timed etch process.

4. The method of claim 1, further comprising removing the portion of the material within the trench using a photolithography process.

5. The method of claim 1, wherein the cladding material comprises a silicon dioxide layer.

6. The method of claim 1, wherein the cladding material comprises a silicon dioxide layer and at least one of silicon nitride layer and a silicon carbide layer.

7. The method of claim 1, wherein the refractive index of the material is less than a refractive index of silicon.

8. The method of claim 1, wherein the material is one of silicon nitride (Si₃N₄), silicon oxide (SiOx), silicon oxynitride (SiON), aluminum oxide (Al₂O₃), and aluminum nitride (AlN).

9. The method of claim 1, wherein a thickness of the material is between 2 micrometers (μ

m) and 20 μ

m.

10. The method of claim 1, wherein a width of the trench is greater than a width of the inversely tapered silicon waveguide, and wherein the width of the trench is greater than 5 μ

m.

11. The method of claim 1, wherein the ridge waveguide has a single-mode condition.

12. The method of claim 1, wherein the ridge waveguide is formed such that a ridge waveguide width is equivalent to a ridge waveguide height.

13. A method of fabricating an edge coupling device, comprising:

forming a trench within a cladding material disposed over an inversely tapered silicon waveguide;

depositing a refractive index material within the trench, wherein the refractive index material has a refractive index between 1.445 and 3.5; and

patterning the refractive index material to form a ridge waveguide within the trench.

14. The method of claim 13, further comprising forming an etch stop layer over the inversely tapered silicon waveguide prior to forming the trench.

15. The method of claim 13, further comprising gradually transferring an optical mode from the inversely tapered silicon waveguide of the edge coupling device to the ridge waveguide as a width of the inversely tapered silicon waveguide narrows.

16. The method of claim 13, wherein a mode size of the edge coupling device corresponds to a size of the ridge waveguide, wherein the ridge waveguide has a single-mode condition, and wherein the mode size is between 3 micrometers (μ

m) and 10 μ

m.

17. The method of claim 13, further comprising monolithically integrating the edge coupling device with a silicon on insulator (SOI) device.