Integrated vector modulator

Patent metadata

Field	Value
Publication number	US-10690850-B2
Application number	US-201816044427-A
Country	US
Kind code	B2
Filing date	Jul 24, 2018
Priority date	Jul 24, 2017
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

A method and apparatus for simultaneously modulating at least two distinct characteristics of an optical carrier propagating in an optical waveguide with at least two electrical signals includes transmitting an optical beam that includes the optical carrier into an optical waveguide defined in electro-optic material, and applying the at least two electrical signals at the same time to generate an electric field in the optical waveguide. The instantaneous predominant orientation of the electric field in the optical waveguide generated by the applied at least two electrical signals depends on the relative instantaneous values of the applied electrical signals. The at least two distinct characteristics of the optical carrier propagating in the optical waveguide are simultaneously and independently modulated depending on the predominant orientation of the electric field in the optical waveguide as a result of the application of the at least two electrical signals.

First claim

We claim:

1. An apparatus for modulating an optical carrier, the apparatus including:
an optical waveguide defined in electro-optic material, said optical waveguide supporting at least two polarization states of light that are orthogonal to one another;
an optical input to couple light into the optical waveguide;
an optical output to couple light out of the optical waveguide; and
at least two signal electrodes to receive modulating electrical signals,
wherein the signal electrodes are both adjacent to the optical waveguide and are positioned to produce an electric field across the optical waveguide when electrical signals are applied to the signal electrodes, and
wherein the signal electrodes are further positioned to enable the generation of at least a first predominant orientation of the electric field across the optical waveguide as a result of a first pair of signals applied to the signal electrodes, and at least a second, different, predominant orientation of the electric field across the optical waveguide as a result of second pair of signals different from the first pair of signals applied to the signal electrodes;
whereby at least two distinct characteristics of light passing through the optical waveguide between the optical input and the optical output are simultaneously and independently modulated as a result of applying each of the first and second pair of electrical signals to the respective signal electrodes.

2. The apparatus of claim 1 , wherein the two distinct characteristics of light include phase and polarization.

3. The apparatus of claim 1 , wherein the electro-optic material is lithium niobate.

4. The apparatus of claim 1 , wherein the electro-optic material is barium titanate.

5. The apparatus of claim 1 , wherein the electro-optic material forms a thin-film layer.

6. The apparatus of claim 5 , wherein the optical waveguide is defined by patterning a strip of dielectric material adjacent to the thin-film layer of electro-optic material.

7. The apparatus of claim 1 , wherein the signal electrodes comprise metal traces parallel to the optical waveguide.

8. The apparatus of claim 7 , wherein from a transverse cross-sectional view of the signal electrodes and the optical waveguide, the signal electrodes extend from a first surface of the electro-optic material away from the electro-optic material in a first direction, and the optical waveguide extends into the electro-optic material beyond the first surface of the electro-optic material in a second direction opposite the first direction.

9. The apparatus of claim 1 , wherein each of the two polarization states of light propagating in the optical waveguide corresponds to an effective refractive index, and substantially the same effective refractive index corresponds to the two polarization states of light propagating in the optical waveguide.

10. The apparatus of claim 1 , wherein the first predominant orientation of the electric field is not orthogonal to the second predominant orientation of the electric field.

11. An apparatus for simultaneously modulating two characteristics of at least one optical beam with two electrical signals, the apparatus including:
an optical waveguide defined in electro-optic material;
said optical waveguide supporting at least two polarization states of light that are orthogonal to one another;
an optical input to couple the two optical beams into the optical waveguide,
an optical output to couple light out of the optical waveguide; and
two signal electrodes to receive modulating electrical signals,
wherein the signal electrodes are both adjacent to the optical waveguide and are positioned to produce an electric field across the optical waveguide when electrical signals are applied at the same time to the signal electrodes,
wherein the signal electrodes are further positioned to enable the generation of at least a first predominant orientation of the electric field across the optical waveguide as a result of first pair of signals applied to the signal electrodes, and at least a second, different, predominant orientation of the electric field across the optical waveguide as a result of second pair of signals different from the first pair of signals applied to the signal electrodes, and
whereby the two characteristics of the at least one optical beam are simultaneously and independently modulated by the electric field generated in the optical waveguide due to the application of the two electrical signals to the two signal electrodes, respectively.

12. The apparatus of claim 11 , wherein:
the at least one optical beam is two optical beams having substantially different polarizations with respect to one another as they are coupled into the optical waveguide; and
the two characteristics of the two optical beams modulated with the two electrical signals include polarization state and relative phase between the two optical beams.

13. The apparatus of claim 11 , wherein the electro-optic material forms a thin-film layer.

14. The apparatus of claim 13 , wherein the optical waveguide is defined by patterning a strip of dielectric material adjacent to the thin-film layer of electro-optic material.

15. The apparatus of claim 11 , wherein:
the at least one optical beam is two optical beams having substantially different polarizations with respect to one another as they are coupled into the optical waveguide; and
substantially the same effective refractive index corresponds to the two polarization states of light propagating in the optical waveguide.

Assignees

• Phase Sensitive Innovations Inc

Inventors

• Murakowski Janusz
• Creazzo Timothy

Classifications

• G02F1/035 Primary

  in an optical waveguide structure · CPC title

• G02F2203/06

  Polarisation independent · CPC title

• G02F1/0154

  using electro-optic effects, e.g. linear electro optic [LEO], Pockels, quadratic electro optical [QEO] or Kerr effect · CPC title

• G02B2006/12147

  Coupler · CPC title

• G02F1/0316

  Electrodes · CPC title