Process for fabrication of optical waveguides

• US 20030176002A1
• Filed: 12/24/2002
• Published: 09/18/2003
• Est. Priority Date: 06/29/2001
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Smith, Terry L., Zhang, Jun-Ying, Koch, Barry J., Gates, Brian J., Larsen, Jeremy K.
• Granted Patent: US 6,946,238 B2
• Time in Patent Office: Days
• US Class Current: 438/22
• CPC Class Codes: G02B 6/132 by deposition of thin films
• CPC Class Codes: G02B 6/136 by etching
• CPC Class Codes: G02B 6/138 by using polymerisation
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: H01S 3/0632 Thin film lasers in which light propagates in the plane of the thin film
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/1603 rare earth
• CPC Class Codes: H01S 3/17 amorphous, e.g. glass
• CPC Class Codes: H01S 5/026 Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers stabilisation of output H01S5/06
• CPC Class Codes: H01S 5/10 Construction or shape of the optical resonator , e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region H01S5/20 takes precedence
• CPC Class Codes: H01S 5/1014 Tapered waveguide, e.g. spotsize converter H01S5/1064 takes precedence
• CPC Class Codes: H01S 5/1064 varying width along the optical axis
• CPC Class Codes: H01S 5/14 External cavity lasers H01S5/18 takes precedence; mode locking H01S5/065
• CPC Class Codes: H01S 5/327 in AIIBVI compounds, e.g. ZnCdSe-laser

Abstract

A method for manufacturing an optical waveguide device in accordance with the present invention includes the steps of depositing a lower cladding layer; coating a photoresist layer directly on the lower cladding layer; patterning the photoresist layer to create channels; depositing a core layer, wherein a first portion of the core layer is deposited inside the channels and a second portion overlays the patterned photoresist layer; removing the patterned photoresist layer and the second portions of the core layer overlaying the patterned photoresist layer; and depositing an upper cladding layer.

Claims

1. A method for manufacturing an optical waveguide device, comprising in order the steps of:

a. depositing a lower cladding layer;

b. coating a photoresist layer directly on the lower cladding layer;

c. patterning the photoresist layer to create channels;

d. depositing a core layer, wherein a first portion of the core layer is deposited inside the channels and a second portion overlays the patterned photoresist layer;

e. removing the patterned photoresist layer and the second portions of the core layer overlaying the patterned photoresist layer; and

f. depositing an upper cladding layer.

2. The method of claim 1, wherein the optical waveguide is a single-mode waveguide.

3. The method of claim 1, the lower optical cladding comprising a substrate of a transparent material having an appropriate index.

4. The method of claim 3, the lower cladding layer including a Ge doped SiO₂ core on an undoped fused quartz substrate.

5. The method of claim 1 where the index of refraction difference between the core layer and the cladding layer is about 0.3%.

6. The method of claim 1 where the optical core layer has a thickness between 0.2 micrometers and 10 micrometers inclusive.

7. The method of claim 1, wherein the optical core layer has a thickness of about 6.5 micrometers and an index of refraction difference between the core layer and the cladding layer of about 0.5%.

8. The method of claim 1, wherein the step of patterning the photoresist layer includes photolithography.

9. The method of claim 1, wherein the step of depositing the core layer comprises plasma enhanced chemical vapor deposition.

10. The method of claim 1, wherein the step of depositing the core layer comprises sputtering.

11. The method of claim 1, further comprising the step of etching the lower cladding in a way that undercuts the photoresist.

12. The method of claim 11, the step of etching the lower cladding including the step of using an anisotropic etchant after the step of patterning the photoresist.

13. The method of claim 1, wherein the steps of depositing includes one of the following:

physical vapor deposition (PVD), sputtering, evaporation, electron beam evaporation, molecular beam epitaxy, pulsed laser deposition, flame hydrolysis deposition (FHD), and more preferably chemical vapor deposition including atmospheric pressure chemical vapor deposition (APCVD), low-pressure chemical vapor deposition (LPCVD), and plasma-enhanced chemical vapor deposition (PECVD).

14. The method of claim 1, further comprising the step of providing a substrate base layer on which to deposit the lower cladding layer.

15. The method of claim 14, wherein the substrate base layer comprises silicon, quartz, or a multicomponent glass.

16. The method of claim 1, further comprising the step of annealing the core and lower cladding layer after the step of removing the photoresist.

17. The method of claim 1, further comprising the step of annealing the optical waveguide.

18. The method of claim 1, wherein the lower cladding layer comprises a material selected from one of the following:

silicon dioxide (SiO2), Magnesium Fluoride, diamond-like glass (DLG);

polymers (acrylate, polyimide;

silicon oxynitride (SiON); and

hybrid organic/inorganic sol-gel materials or _boron- or fluorine-doped SiO₂.

19. The method of claim 1, wherein the core layer comprises a materials selected from one of the following:

silicon dioxide doped with titanium, zirconium, germanium, tantalum, hafnium, erbium, phosphorus, silver, nitrogen, or a sputtered multicomponent glass.

20. The method of claim 1, wherein the cladding includes SiO₂ and the core includes SiO₂ doped with Ge, P, Ti, or N.

21. The method of claim 1, wherein the photoresist is a positive photoresist.

22. The method of claim 1, wherein the photoresist is a negative photoresist.

23. The method of claim 1, wherein the step of patterning the photoresist includes applying a photolithography process to the photoresist layer.

24. The method of claim 1, wherein the step of patterning the photoresist includes using e-beam lithography.

25. The method of claim 1, wherein the step of patterning the photoresist layer includes patterning a plurality of vias to receive an array of optical waveguides.

26. An optical splitter manufactured in accordance with the method of claim 1.

27. An optical circuit including waveguides fabricated by the process of claim 1.

28. An active waveguide device including waveguides fabricated from electrooptic materials patterned into waveguides by the method of claim 1.

29. A waveguide manufactured in accordance with the method of claim 1.