Electro-optic combiner and associated methods

Patent metadata

Field	Value
Publication number	US-11493694-B2
Application number	US-202117353789-A
Country	US
Kind code	B2
Filing date	Jun 21, 2021
Priority date	Jun 24, 2020
Publication date	Nov 8, 2022
Grant date	Nov 8, 2022

Abstract

An electro-optic combiner includes a polarization splitter and rotator (PSR) that directs a portion of incoming light having a first polarization through a first optical waveguide (OW). The PSR rotates a portion of the incoming light having a second polarization to the first polarization to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Each of the first and second OW's has a respective combiner section. The first and second OW combiner sections extend parallel to each other and have opposite light propagation directions. A plurality of ring resonators is disposed between the combiner sections of the first and second OW's and within an evanescent optically coupling distance of both the first and second OW's. Each of ring resonators operates at a respective resonant wavelength to optically couple light from the combiner section of the first OW into the combiner section of the second OW.

First claim

What is claimed is:

1. An electro-optic combiner, comprising:
a polarization splitter and rotator having an optical input optically connected to receive incoming light, the polarization splitter and rotator having a first optical output and a second optical output, the polarization splitter and rotator configured to direct a first portion of the incoming light having a first polarization through the first optical output, the polarization splitter and rotator configured to rotate a polarization of a second portion of the incoming light from a second polarization to the first polarization so that the second portion of the incoming light is a polarization-rotated second portion of the incoming light, the polarization splitter and rotator configured to direct the polarization-rotated second portion of the incoming light through the second optical output;
a first optical waveguide having a first end and a second end, the first end of the first optical waveguide optically connected to the first optical output of the polarization splitter and rotator;
a second optical waveguide having a first end and a second end, the first end of the second optical waveguide optically connected to the second optical output of the polarization splitter and rotator; and
a plurality of ring resonators disposed between a combiner section of the first optical waveguide and a combiner section of the second optical waveguide, each of the plurality of ring resonators positioned within an evanescent optically coupling distance of both the first optical waveguide and the second optical waveguide, wherein a light propagation direction through the combiner section of the first optical waveguide is opposite of a light propagation direction through the combiner section of the second optical waveguide, wherein each of the plurality of ring resonators is configured to operate at a respective resonant wavelength, such that light having a wavelength substantially equal to the respective resonant wavelength of a given one of the plurality of ring resonators optically couples light from the combiner section of the first optical waveguide into the given one of the plurality of ring resonators and from the given one of the plurality of ring resonators into the second optical waveguide.

2. The electro-optic combiner as recited in claim 1 , wherein the second optical waveguide includes a change in direction of about 180 degrees before the combiner section of the second optical waveguide with respect to the light propagation direction through the second optical waveguide.

3. The electro-optic combiner as recited in claim 1 , wherein the combiner section of the first optical waveguide and the combiner section of the second optical waveguide are oriented to extend substantially parallel to each other.

4. The electro-optic combiner as recited in claim 1 , further comprising:
a plurality of phase shifters interfaced with to the first optical waveguide, the plurality of phase shifters respectively positioned before the plurality of ring resonators with respect to the light propagation direction through the combiner section of the first optical waveguide, each of the plurality of phase shifters configured to apply a controlled amount of shift to a phase of light traveling through the first optical waveguide.

5. The electro-optic combiner as recited in claim 4 , further comprising:
one or more photodetectors optically connected to the second optical waveguide at a location after the combiner section of the second optical waveguide with respect to the light propagation direction through the combiner section of the second optical waveguide.

6. The electro-optic combiner as recited in claim 5 , wherein photocurrents generated by the one or more photodetectors provide for feedback control of the plurality of phase shifters.

7. The electro-optic combiner as recited in claim 4 , wherein one or more of the plurality of phase shifters is/are implemented as a thermal tuner.

8. The electro-optic combiner as recited in claim 4 , wherein one or more of the plurality of phase shifters is/are implemented as a diode.

9. The electro-optic combiner as recited in claim 4 , wherein one or more of the plurality of phase shifters is/are implemented as a ring resonator.

10. An electro-optic combiner, comprising:
a polarization splitter and rotator having an optical input optically connected to receive incoming light, the polarization splitter and rotator having a first optical output and a second optical output, the polarization splitter and rotator configured to direct a first portion of the incoming light having a first polarization through the first optical output, the polarization splitter and rotator configured to rotate a polarization of a second portion of the incoming light from a second polarization to the first polarization so that the second portion of the incoming light is a polarization-rotated second portion of the incoming light, the polarization splitter and rotator configured to direct the polarization-rotated second portion of the incoming light through the second optical output;
a first optical waveguide optically connected to the first optical output of the polarization splitter and rotator;
a first plurality of ring resonators positioned along the first optical waveguide such that the phase shifter is positioned alongside the first optical waveguide before the first plurality of ring resonators relative to a direction of light propagation through the first optical waveguide, each of the first plurality of ring resonators positioned within an evanescent optical coupling distance of the first optical waveguide;
a second optical waveguide optically connected to the second optical output of the polarization splitter and rotator;
a second plurality of ring resonators positioned along the second optical waveguide and within an evanescent optical coupling distance of the second optical waveguide, each of the second plurality of ring resonators positioned to optically in-couple light from a respective one of the first plurality of ring resonators and optically out-couple light into the second optical waveguide.

11. The electro-optic combiner as recited in claim 10 , wherein a length of the first optical waveguide between the polarization splitter and rotator and the first plurality of ring resonators is longer than a length of the second optical waveguide between the polarization splitter and rotator and the second plurality of ring resonators, such that the polarization-rotated second portion of the incoming light arrives at the second plurality of ring resonators at about a same time that the first portion of the incoming light arrives at the first plurality of ring resonators.

12. The electro-optic combiner as recited in claim 10 , wherein the second optical waveguide is routed to one or more photodetectors after extending past all of the second plurality of ring resonators.

13. The electro-optic combiner as recited in claim 10 , wherein each of the first plurality of ring resonators is configured to operate at a respective resonant wavelength, such that light having a wavelength substantially equal to the respective resonant wavelength of a given one of the first plurality of ring resonators optically couples from the first optical waveguide into the given one of the first plurality of ring resonators, and wherein each of the second plurality of ring resonators is optically coupled to a corresponding one of the first plurality of ring resonators and is configured to operate at a respective resonant wavelength substantially equal to that of the corresponding one of the first plurality of ring resonators.

Assignees

• Ayar Labs Inc

Inventors

• Bhargava Pavan
• Van Orden Derek
• Wade Mark
• Fini john
• Sun Chen
• Popovic Milos
• Khilo Anatol

Classifications

• G02B6/2773

  Polarisation splitting or combining · CPC title

• G02B6/272

  comprising polarisation means for beam splitting and combining · CPC title

• G02B6/2793

  Controlling polarisation dependent loss, e.g. polarisation insensitivity, reducing the change in polarisation degree of the output light even if the input polarisation state fluctuates · CPC title

• G02B6/29343 Primary

  Cascade of loop resonators · CPC title

• G02B6/34

  utilising prism or grating {(G02B6/293 takes precedence)} · CPC title