Nanoscale plasmonic field-effect modulator

Patent metadata

Field	Value
Publication number	US-9864109-B2
Application number	US-201615331435-A
Country	US
Kind code	B2
Filing date	Oct 21, 2016
Priority date	Apr 4, 2013
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A plasmonic device having a transparent conducting oxide (TCO) waveguide and a tunable voltage applied across the TCO and a metal layer for modulating an input optical signal.

First claim

What is claimed is:

1. An optical modulator, comprising:
a substrate;
a metal layer on the substrate, the metal layer having a grooved channel;
a dielectric layer on the metal layer and in the grooved channel; and
a transparent conducting oxide (TCO) on the dielectric layer and in the grooved channel, wherein the optical modulator is controlled by an electrical bias voltage applied to the TCO and to the metal layer, and
wherein a plasmonic waveguide is modulated in the grooved channel due to a field effect from the electrical bias voltage applied to the TCO and the metal layer, and an input optical signal propagates inside the grooved channel; and
wherein the TCO is insulated from the metal layer by the dielectric layer.

2. The optical modulator of claim 1 , wherein the grooved channel comprises a stub extending substantially perpendicularly to the grooved channel.

3. The optical modulator of claim 2 , wherein the stub is formed near a center section of a length of the grooved channel.

4. The optical modulator of claim 2 , wherein the stub forms a cavity resonator in the grooved channel.

5. The optical modulator of claim 2 , wherein the stub comprises two or more stubs, each of the stubs being spaced from one another.

6. An optical modulator, comprising:
a substrate;
a metal layer on the substrate, the metal layer having a grooved channel;
a dielectric layer on the metal layer and in the grooved channel; and
a transparent conducting oxide (TCO) on the dielectric layer and in the grooved channel, wherein the optical modulator is controlled by an electrical bias voltage applied to the TCO and to the metal layer, and
wherein a plasmonic waveguide is modulated in the grooved channel due to a field effect from the electrical bias voltage applied to the TCO and the metal layer, and an input optical signal propagates inside the grooved channel; and
wherein the optical modulator includes a first metal-dielectric interface and a second metal-dielectric interface, the first and the second metal-dielectric interfaces are positioned facing each other and defining a gap comprising TCO therebetween, and the input optical signal propagates in a gap plasmonic mode within the gap defined between the first and the second metal-dielectric interfaces.

7. The optical modulator of claim 6 , wherein the gap is disposed within the grooved channel.

8. The optical modulator of claim 6 , wherein a first electrical bias applied to the TCO is different from a second electrical bias applied to the metal layer.

9. The optical modulator of claim 6 , wherein the grooved channel comprises a first end of the grooved channel at a first edge of the metal layer, and a second end of the grooved channel at a second edge of the metal layer.

10. The optical modulator of claim 9 , wherein the optical input signal is configured to be applied to the grooved channel at the first end, and a modulated optical signal is configured to be outputted at the second end.

11. The optical modulator of claim 9 , wherein the optical signal applied to the first end of the grooved channel is output from the second end of the grooved channel.

12. The optical modulator of claim 6 , wherein an entire portion of the grooved channel is covered with the TCO.

13. The optical modulator of claim 6 , wherein the grooved channel comprises a section having a first width and a section having a second width, wherein the width of the groove varies gradually from the first width to the second width, and from the second width to the first width.

14. The optical modulator of claim 13 , wherein the first width is wider than the second width.

15. The optical modulator of claim 6 , wherein the grooved channel is V-shaped.

16. The optical modulator of claim 6 , wherein the TCO is selected from the group consisting of: indium tin oxide (ITO), gallium zinc oxide (Ga:ZnO), and aluminum zinc oxide (Al:ZnO).

17. The optical modulator of claim 6 , wherein the metal layer is a gold layer or a silver layer.

18. The optical modulator of claim 6 , wherein the grooved channel in the metal layer extends to the substrate.

Assignees

• California Inst Of Techn

Inventors

• Lee Ho Wai
• Burgos Stanley
• Papadakis Georgia
• Atwater Harry A

Classifications

• G02F1/0356

  controlled by a high-frequency electromagnetic wave component in an electric waveguide structure · CPC title

• G02B5/008 Primary

  Surface plasmon devices (diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553) · CPC title

• G02F2203/15

  involving resonance effects, e.g. resonantly enhanced interaction · CPC title

• G02F2203/10

  plasmon · CPC title

• G02F1/011

  in optical waveguides, not otherwise provided for in this subclass · CPC title