TFP optical transition device and method

Patent metadata

Field	Value
Publication number	US-11435603-B2
Application number	US-202017070749-A
Country	US
Kind code	B2
Filing date	Oct 14, 2020
Priority date	Oct 14, 2020
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A thin film polymer device including a waveguide core surrounded by dielectric material positioned on a platform. The core has a passive input portion and a passive output portion joined by a necked down active portion. A layer of EO polymer material positioned on the dielectric material overlying the active portion of the core and the core, the EO polymer, and the dielectric material all having refractive indices with the refractive index of the EO polymer being higher than the refractive index of the dielectric material. Light progressing through the core from the passive input portion to the passive output portion transitions to the layer of EO polymer material as it enters the necked down active portion and transitions back to the core as it leaves the necked down active portion.

First claim

Having fully described the invention in such clear and concise terms as to enable those skilled in the art to understand and practice the same, the invention claimed is:

1. A thin film polymer device comprising:
a platform;
at least one waveguide core surrounded by dielectric material positioned on the platform, the waveguide core having a passive input portion and a passive output portion joined by a necked down active portion;
a layer of EO polymer material positioned on a surface of the dielectric material overlying the necked down active portion of the waveguide core;
the waveguide core, the EO polymer, and the dielectric material all having refractive indices with the refractive index of the EO polymer being higher than the refractive index of the dielectric material; and
at least some light progressing through the waveguide core from the passive input portion to the passive output portion transitions to the layer of EO polymer material as it enters the necked down active portion and transitions back to the waveguide core as it leaves the necked down active portion.

2. The thin film polymer device claimed in claim 1 wherein the at least one waveguide core includes a pair of similar waveguide cores spaced apart in a plane and extending parallel to each other.

3. The thin film polymer device claimed in claim 2 wherein the layer of EO polymer material is included in a single polymer layer device assembly, the device assembly includes a silicon base having an oxidized surface, metallization on the oxidized surface defining electrodes for operating the thin film polymer device, a bottom clad layer on the electrodes forming a planar surface, a blocking layer on the planar surface, and the layer of EO polymer material positioned on the blocking layer.

4. The thin film polymer device claimed in claim 3 wherein the single polymer layer device assembly is positioned on the dielectric material surrounding the at least one waveguide core with a surface of the layer of EO polymer material in abutting engagement with the dielectric material surrounding the at least one waveguide core.

5. The thin film polymer device claimed in claim 3 including a layer of transparent glue affixing a surface of the dielectric material surrounding the at least one waveguide core to a surface of the layer of EO polymer material.

6. The thin film polymer device claimed in claim 1 wherein the width of the necked down active portion of the waveguide core is gradually reduced from the width of the passive input portion and gradually increased to the width of the passive output portion.

7. The thin film polymer device claimed in claim 1 wherein the at least one waveguide core includes a pair of similar waveguide cores spaced apart in a plane and extending parallel to each other and electrodes positioned adjacent the layer of EO polymer material, the pair of similar waveguide cores, the layer of EO polymer material, and the electrodes being positioned to form a Mach-Zehnder modulator.

8. The thin film polymer device claimed in claim 1 wherein the passive input portion and the passive output portion of the at least one waveguide core has a horizontal width in a range of 0.1 μm to 10 μm and the necked down active portion has a horizontal width in a range of 2:1 to 5:1, where the ratio is the passive portion width to the active portion width.

9. The thin film polymer device claimed in claim 1 wherein the passive input portion and the passive output portion of the at least one waveguide core each have a horizontal width in a range of 0.5 μm to 8 μm and the necked down active portion has a horizontal width reduced by greater than 0.4 μm.

10. A thin film polymer device comprising:
a silicon substrate defining a platform;
a pair of similar waveguide cores spaced apart in a plane and extending parallel to each other, the pair of waveguide cores surrounded by dielectric material positioned on the platform, each of pair of waveguide cores having a passive input portion and a passive output portion joined by a necked down active portion;
a layer of EO polymer material positioned on a surface of the dielectric material overlying the necked down active portion of the waveguide core;
electrodes positioned adjacent to the layer of EO polymer material and in a spaced relationship to the pair of waveguide cores;
the waveguide core, the EO polymer, and the dielectric material all having refractive indices with the refractive index of the EO polymer being higher than the refractive index of the dielectric material; and
the pair of similar waveguide cores, the layer of EO polymer material, and the electrodes being positioned to form a Mach-Zehnder modulator in which at least some light progressing through the waveguide core from the passive input portion to the passive output portion transitions to the layer of EO polymer material as it enters the necked down active portion and transitions back to the waveguide core as it leaves the necked down active portion.

11. The thin film polymer device claimed in claim 10 wherein the passive input portion and the passive output portion of the at least one waveguide core has a horizontal width in a range of 0.1 μm to 10 μm and the necked down active portion has a horizontal width in a range of 2:1 to 5:1, where the ratio is the passive portion width to the active portion width.

12. The thin film polymer device claimed in claim 10 wherein the passive input portion and the passive output portion of the at least one waveguide core each have a horizontal width in a range of 0.5 μm to 8 μm and the necked down active portion has a horizontal width reduced by greater than 0.4 μm.

13. A method of fabricating a thin film polymer device comprising the steps of;
fabricating a single polymer layer device assembly including the steps of:
providing a silicon base having an oxidized surface;
depositing a metallization layer on the oxidized surface and patterning the metallization layer to define electrodes for operating the thin film polymer device;
depositing a bottom clad layer on the electrodes forming a planar surface;
depositing a blocking layer on the planar surface of the bottom clad layer; and
depositing a layer of EO polymer material on the blocking layer;

fabricating a waveguide layout including a pair of similar waveguide cores spaced apart in a plane and extending parallel to each other, the pair of waveguide cores surrounded by dielectric material positioned on a platform, each of the pair of waveguide cores having a passive input portion and a passive output portion joined by a necked down active portion; and
affixing a surface of the EO polymer material to a surface of the dielectric material on the platform with the electrodes positioned relative to the necked down active portions of the pair of similar waveguide cores to form a Mach-Zehnder modulator.

14. The method of fabricating a thin film polymer device as claimed in claim 13 including a step of poling the layer of EO polymer material.

15. The method of fabricating a thin film polymer device as claimed in claim 13 wherein step of affixing includes one of bonding using a flip-chip bonding method or including a transparent layer of glue between the surface of the EO polymer material and the surface of the dielectric material on the platform.

16. The method of fabricating a thin film polymer device as claimed in claim 13 wherein the step of fabricating a waveguide layout including a pair of similar waveguide cores includes forming the waveguide core with a horizontal width in a range of 0.1 μm to 10 μm and the necked down active portio

Assignees

• Lightwave Logic Inc

Inventors

• Leonberger Frederick J
• Liu Karen
• Lebby Michael

Classifications

• G02F1/065 Primary

  in an optical waveguide structure · CPC title

• G02F1/212

  Mach-Zehnder type · CPC title

• G02F1/225

  in an optical waveguide structure · CPC title