Waveguide mode expander having an amorphous-silicon shoulder

• US 10,001,600 B2
• Filed: 04/14/2017
• Issued: 06/19/2018
• Est. Priority Date: 05/27/2014
• Status: Active Grant

• Current Assignee: Skorpios Technologies Inc.
• Original Assignee: Skorpios Technologies Inc.
• Inventors: Li, Guoliang, Lambert, Damien, Kumar, Nikhil
• Primary Examiner(s): Ullah, Akm Enayet
• Application Number:
  US15/487,918
• Publication Number:
  US 20170351028A1
• Time in Patent Office: 431 Days
• CPC Class Codes: G02B 2006/12038 Glass (SiO2 based materials)
• CPC Class Codes: G02B 2006/12061 Silicon
• CPC Class Codes: G02B 2006/12097 Ridge, rib or the like
• CPC Class Codes: G02B 2006/12147 Coupler
• CPC Class Codes: G02B 2006/12152 Mode converter
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/132 by deposition of thin films
• CPC Class Codes: G02B 6/136 by etching
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide

Abstract

A waveguide mode expander couples a smaller optical mode in a semiconductor waveguide to a larger optical mode in an optical fiber. The waveguide mode expander comprises a shoulder and a ridge. In some embodiments, the ridge of the waveguide mode expander has a plurality of stages, the plurality of stages having different widths at a given cross section.

Claims

1. A method for manufacturing a waveguide mode expander, the method comprising:

providing a substrate having a device layer disposed on the substrate;

applying photoresist on the device layer;

etching the device layer to form a first recess, the first recess having a shape of a first pattern;

removing photoresist from the device layer;

filling the first recess with non-crystalline silicon to form a shoulder;

etching the device layer to define a waveguide;

etching the shoulder to align with the waveguide;

covering the shoulder with cladding;

applying photoresist on the cladding;

etching the cladding to form a second recess, the second recess having a shape of a second pattern;

removing photoresist from the cladding; and

filling the second recess with non-crystalline silicon, wherein;

the non-crystalline silicon forms a ridge of the waveguide mode expander;

the shoulder is between the substrate and the ridge; and

the ridge has a narrower width than the shoulder.

2. The method for manufacturing a waveguide mode expander of claim 1, wherein etching the cladding uses a highly selective etch such that the cladding is more easily etched than the shoulder.

3. The method for manufacturing a waveguide mode expander of claim 1, wherein the second pattern comprises a triangle taper.

4. The method for manufacturing a waveguide mode expander of claim 1, wherein the second pattern comprises a parabolic taper.

5. The method for manufacturing a waveguide mode expander of claim 1, further comprising:

applying, wherein the cladding is a first cladding, a second cladding on both the first cladding and the non-crystalline silicon;

etching the second cladding to form a third recess, the third recess having a shape of a third pattern; and

filling the third recess with additional non-crystalline silicon to form a second stage of the ridge, wherein filling the second recess formed a first stage of the ridge.

6. The method for manufacturing a waveguide mode expander of claim 5, wherein:

the first stage is wider than the second stage; and

the second stage is thicker than the first stage.

7. The method for manufacturing a waveguide mode expander of claim 5, further comprising:

applying, a third cladding the second cladding;

etching the third cladding to form a fourth recess, the fourth recess having a shape of a fourth pattern; and

filling the fourth recess with additional non-crystalline silicon to form a third stage of the ridge.

8. The method for manufacturing a waveguide mode expander of claim 1, wherein filling the first recess with non-crystalline silicon comprises filling the first recess with amorphous silicon.

9. The method for manufacturing a waveguide mode expander of claim 8, the method further comprising converting the amorphous silicon to polycrystalline silicon.