Electro-optical Phase Modulator Having Stitched-in Vacuum Stable Waveguide with Minimized Conductivity Contrast

Patent metadata

Field	Value
Publication number	US-2017370723-A1
Application number	US-201715633795-A
Country	US
Kind code	A1
Filing date	Jun 27, 2017
Priority date	Jun 28, 2016
Publication date	Dec 28, 2017
Grant date	—

Abstract

A Y-branch dual electro-optical phase modulator (YBDPM) has a stitched-in zinc oxide diffused waveguide. It is more vacuum stable and has higher resistance to photorefractive damage than currently used Ti-diffused waveguides. The YBDPM is useful in Fiber Optic Gyroscopes (FOG), especially in low frequencies applications.

First claim

What is claimed is:

1 . An optical phase modulator, comprising:
a lithium niobate substrate; a proton-exchanged waveguide section formed on the substrate; and a zinc oxide diffused stitched-in waveguide section formed on the substrate and optically coupled to the proton-exchanged waveguide section.

2 . A modulator as claimed in claim 1 , wherein the proton-exchanged waveguide section comprises a Y-junction, a first branch waveguide portion, and a second branch waveguide portion.

3 . A modulator as claimed in claim 2 , wherein the zinc oxide diffused stitched-in waveguide section comprises a first stitched-in waveguide portion optically coupled to the first branch waveguide portion, a second stitched-in waveguide portion optically coupled to the second branch waveguide portion, and a plurality of electrodes proximate to the first and second stitched-in waveguide portions.

4 . A modulator as claimed in claim 3 , wherein the proton-exchanged waveguide section further comprises a first distal side waveguide portion optically coupled to the first stitched-in waveguide portion; and a second distal side waveguide portion optically coupled to the second stitched-in waveguide portion.

5 . A modulator as claimed in claim 3 , wherein the first and second zinc oxide diffused stitched-in waveguide portions extend substantially parallel to crystal planes of the substrate.

6 . A modulator as claimed in claim 3 , wherein coupling locations between the zinc oxide diffused stitched-in waveguide section and the proton-exchanged waveguide section are separated from the plurality of electrodes by greater than 0.1 mm.

7 . A fiber optic gyroscope, comprising:
a light source for generating light; a fiber coil through which the light is transmitted; and an optical phase modulator for modulating the light, wherein the optical phase modulator includes: a lithium niobate substrate, a proton-exchanged waveguide section formed on the substrate, and a zinc oxide diffused stitched-in waveguide section formed on the substrate and optically coupled to the proton-exchanged waveguide section.

8 . A gyroscope as claimed in claim 7 , wherein the proton-exchanged waveguide section comprises a Y-junction, a first branch waveguide portion, and a second branch waveguide portion.

9 . A gyroscope as claimed in claim 8 , wherein the zinc oxide diffused stitched-in waveguide section comprises a first stitched-in waveguide portion optically coupled to the first branch waveguide portion, a second stitched-in waveguide portion optically coupled to the second branch waveguide portion, and a plurality of electrodes proximate to the first and second stitched-in waveguide portions.

10 . A gyroscope as claimed in claim 9 , wherein the proton-exchanged waveguide section further comprises a first distal side waveguide portion coupled to the first stitched-in waveguide portion; and a second distal side waveguide portion coupled to the second stitched-in waveguide portion.

11 . A gyroscope as claimed in claim 9 , wherein the first and second zinc oxide diffused stitched-in waveguide portions extends substantially parallel to crystal planes of the substrate.

12 . A gyroscope as claimed in claim 9 , wherein coupling locations between the zinc oxide diffused stitched-in waveguide section and the proton-exchanged waveguide section are separated from the plurality of electrodes by greater than 0.1 mm.

13 . A method of fabricating an optical phase modulator, comprising:
providing a lithium niobate substrate; forming a proton-exchanged waveguide section on the substrate; and forming a zinc oxide diffused stitched-in waveguide section on the substrate that is optically coupled to the proton-exchanged waveguide section.

14 . A method as claimed in claim 13 , wherein forming the proton-exchanged waveguide section comprises forming a Y-junction, a first branch waveguide portion, and a second branch waveguide portion.

15 . A method as claimed in claim 14 , wherein forming the zinc oxide diffused stitched-in waveguide section comprises forming a first stitched-in waveguide portion optically coupled to the first branch waveguide portion, forming a second stitched-in waveguide portion coupled to the second branch waveguide portion, and forming a plurality of electrodes proximate to the first and second stitched-in waveguide portions.

16 . A method as claimed in claim 15 , wherein forming the proton-exchanged waveguide section further comprises forming a first distal side waveguide portion optically coupled to the first stitched-in waveguide portion; and forming a second distal side waveguide portion optically coupled to the second stitched-in waveguide portion.

17 . A method as claimed in claim 15 , wherein the first and second zinc oxide diffused stitched-in waveguide portions extend substantially parallel to crystal planes of the substrate.

18 . A method as claimed in claim 15 , wherein coupling locations between the zinc oxide diffused stitched-in waveguide section and the proton-exchanged waveguide section are separated from the plurality of electrodes by greater than 0.1 mm.

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Feke Gilbert D

Classifications

• G02F2202/20

  LiNbO3, LiTaO3 · CPC title

• G02F1/225 Primary

  in an optical waveguide structure · CPC title

• G02F2201/06

  integrated waveguide · CPC title

• G02F1/035

  in an optical waveguide structure · CPC title

• G01C19/722 Primary

  of the mechanical construction · CPC title