Plasmon-assisted optical vias for photonic ASICS

• US 9,599,781 B1
• Filed: 09/08/2015
• Issued: 03/21/2017
• Est. Priority Date: 09/11/2014
• Status: Active Grant

• Current Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.)
• Original Assignee: Sandia Corporation (Martin Marietta Corporation)
• Inventors: Skogen, Erik J., Vawter, Gregory A., Tauke-Pedretti, Anna
• Primary Examiner(s): KIM, ELLEN E
• Application Number:
  US14/847,806
• Time in Patent Office: 560 Days
• Field of Search: 385/50, 385129-132, 385/28
• US Class Current: 1/1
• CPC Class Codes: G02B 6/12002 Three-dimensional structures
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/1226 involving surface plasmon interaction
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/264 with optical elements between opposed fibre ends which perform a function other than beam splitting having lens focusing means G02B6/32; utilising prism or grating G02B6/34
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02B 6/4218 Optical features

Abstract

The present invention relates to optical vias to optically connect multilevel optical circuits. In one example, the optical via includes a surface plasmon polariton waveguide, and a first optical waveguide formed on a first substrate is coupled to a second optical waveguide formed on a second substrate by the surface plasmon polariton waveguide. In some embodiments, the first optical waveguide includes a transition region configured to convert light from an optical mode to a surface plasmon polariton mode or from a surface plasmon polariton mode to an optical mode.

Claims

1. A multilevel optical circuit, comprising:

a first layer that contains one or more first optical waveguides;

a second layer that contains one or more second optical waveguides; and

one or more optical vias, each of the optical vias being configured to optically connect a first optical waveguide to a second optical waveguide, wherein;

each of the optical vias comprises a surface plasmon polariton (SPP) waveguide;

the circuit further comprises a respective photon-to-plasmon transition region that couples each of the optical vias to a first optical waveguide; and

the circuit further comprises a respective plasmon-to-photon transition region that couples each of the optical vias to a second optical waveguide.

2. The multilevel optical circuit of claim 1, wherein the first and second layers extend laterally in two horizontal dimensions and have respective thicknesses in a vertical dimension, and wherein the one or more optical vias are substantially perpendicular to the first and second layers so that said vias extend substantially in the vertical dimension.

3. The multilevel optical circuit of claim 1, wherein at least part of each photon-to-plasmon transition region is coplanar with its connected first optical waveguide or at least part of each plasmon-to-photon transition region is coplanar with its connected second optical waveguide.

4. The multilevel optical circuit of claim 1, wherein at least part of each photon-to-plasmon transition region is collinear with its connected SPP waveguide.

5. The multilevel optical circuit of claim 1, wherein at least part of each plasmon-to-photon transition region is collinear with its connected SPP waveguide.

6. The multilevel optical circuit of claim 1, wherein each optical via extends through a dielectric layer that separates the first layer from the second layer.

7. The multilevel optical circuit of claim 1, wherein:

one of the first and second waveguides is a semiconductor waveguide, and

the other of the first and second waveguides is a polymer waveguide.

8. The multilevel optical circuit of claim 1, wherein each SPP waveguide comprises a metal film on a dielectric layer.

9. The multilevel optical circuit of claim 1, wherein each of the optical vias connects a first optical waveguide to a second optical waveguide with an optical coupling loss less than about 10 percent and an optical propagation loss less than about 1 dB in polarization contrast.

10. The multilevel optical circuit of claim 1, wherein the optical coupling effectuated by each of the optical vias and its respective photon-to-plasmon and plasmon-to-photon transition regions occupies a footprint that is no larger than 10 μ

m×

10 μ

m.

11. The multilevel optical circuit of claim 1, wherein each of the SPP waveguides is less than 100 μ

m long.

12. The multilevel optical circuit of claim 1, wherein each of the photon-to-plasmon transition regions has a tapered shape.

13. The multilevel optical circuit of claim 12, wherein the tapered shape is triangular.

14. The multilevel optical circuit of claim 1, wherein each of the plasmon-to-photon transition regions has an expanded shape.

15. The multilevel optical circuit of claim 14, wherein the expanded shape is trapezoidal.