Granted Patent B1

US 12,372,725 · App. 18/228,619 · Granted Jul 29, 2025

Inventor: Mark Thompson (Palo Alto, CA)

Assignee: PsiQuantum Corp.

G02B6/2821G02B6/12002G02B6/1228G02B6/125G02F1/212G02F1/225G02F1/3132G02F1/3133G02F1/3135G02B2006/1209

Abstract

Claims (86)

1. An optical coupler, comprising:

a first waveguide including a first multi-mode waveguide section; and

a second waveguide that is distinct and separate from the first waveguide, the second waveguide including a second multi-mode waveguide section that is distinct and separate from the first multi-mode waveguide section, wherein:

the first multi-mode waveguide section has a cross-section characterized by a first height and a first width that is greater than the first height;

the second multi-mode waveguide section has a cross-section characterized by a second height and a second width that is greater than the second height;

the first multi-mode waveguide section is positioned adjacent to the second multi-mode waveguide section at least partially above or below the second multi-mode waveguide section so that light entering the first multi-mode waveguide section is coupled from the first multi-mode waveguide section to the second multi-mode waveguide section; and

the first multi-mode waveguide section and the second multi-mode waveguide section are separated by a first edge-to-edge distance so that light entering the first multi-mode waveguide section in a fundamental mode is coupled from the first multi-mode waveguide section to the second multi-mode waveguide section while remaining in the fundamental mode.

2. The optical coupler of claim 1 , wherein:

the first width is at least three times the first height; and

the second width is at least three times the second height.

3. The optical coupler of claim 1 , wherein:

the first waveguide includes a third multi-mode waveguide section that is distinct from, and mutually exclusive to, the first multi-mode waveguide section so that light propagating in the third multi-mode waveguide section propagates toward the first multi-mode waveguide section; and

the second waveguide includes a fourth multi-mode waveguide section that is distinct from, and mutually exclusive to, the second multi-mode waveguide section so that light propagating in the fourth multi-mode waveguide section propagates toward the second multi-mode waveguide section.

4. The optical coupler of claim 3 , wherein:

the first waveguide includes a fifth multi-mode waveguide section that is coupled to the first multi-mode waveguide section on a first end and to the third multi-mode waveguide section on a second end that is opposite to the first end; and

the second waveguide includes a sixth multi-mode waveguide section that is coupled to the second multi-mode waveguide section on a first end and to the fourth multi-mode waveguide section on a second end that is opposite to the first end,

wherein at least one of the fifth multi-mode waveguide section and the sixth multi-mode waveguide section is curved.

5. The optical coupler of claim 4 , wherein:

the first waveguide includes a seventh multi-mode waveguide section that is distinct from, and mutually exclusive to, the first multi-mode waveguide section so that light propagating in the first multi-mode waveguide section propagates toward the seventh multi-mode waveguide section; and

the second waveguide includes an eighth multi-mode waveguide section that is distinct from, and mutually exclusive to, the second multi-mode waveguide section so that light propagating in the second multi-mode waveguide section propagates toward the eighth multi-mode waveguide section.

6. The optical coupler of claim 5 , wherein:

the first waveguide includes a ninth multi-mode waveguide section that is coupled to the first multi-mode waveguide section on a first end and to the seventh multi-mode waveguide section on a second end that is opposite to the first end; and

the second waveguide includes a tenth multi-mode waveguide section that is coupled to the second multi-mode waveguide section on a first end and to the eighth multi-mode waveguide section on a second end that is opposite to the first end,

wherein at least one of the ninth multi-mode waveguide section and the tenth multi-mode waveguide section is curved.

7. The optical coupler of claim 1 , wherein:

the first waveguide includes a first single-mode input waveguide section adiabatically coupled to the first multi-mode waveguide section so that the first multi-mode waveguide section receives light from the first single-mode input waveguide section; and

the second waveguide includes a second single-mode input waveguide section adiabatically coupled to the second multi-mode waveguide section so that the second multi-mode waveguide section receives light from the second single-mode input waveguide section.

8. The optical coupler of claim 7 , further comprising:

a first tapered waveguide section, in the first waveguide, configured to enable the adiabatic coupling of the first single-mode input waveguide section to the first multi-mode waveguide section; and

a second tapered waveguide section, in the second waveguide, configured to enable the adiabatic coupling of the second single-mode input waveguide section to the second multi-mode waveguide section.

9. The optical coupler of claim 8 , further comprising:

in the first waveguide:

a first single-mode output waveguide section adiabatically coupled to the first multi-mode waveguide section so that the first single-mode output waveguide section receives light from the first multi-mode waveguide section; and

a third tapered waveguide section configured to enable the adiabatic coupling of the first multi-mode waveguide section to the first single-mode output waveguide section; and

in the second waveguide:

a second single-mode output waveguide section adiabatically coupled to the second multi-mode waveguide section so that the second single-mode output waveguide section receives light from the second multi-mode waveguide section; and

a fourth tapered waveguide section configured to enable the adiabatic coupling of the second multi-mode waveguide section to the second single-mode output waveguide section.

10. The optical coupler of claim 1 , wherein the first multi-mode waveguide section and the second multi-mode waveguide section are parallel to each other.

11. A multi-channel multi-mode optical coupler, comprising:

two or more multi-mode optical couplers, including a first multi-mode optical coupler that corresponds to the optical coupler of claim 1 , wherein:

the first waveguide is located in a first layer of material;

the second waveguide is located in a second layer of material that is distinct and separate from the first layer of material; and

the first multi-mode waveguide section is positioned adjacent to the second multi-mode waveguide section.

12. The multi-channel multi-mode optical coupler of claim 11 , wherein:

the two or more multi-mode optical couplers also include a second multi-mode optical coupler that includes:

a third waveguide including a third multi-mode waveguide section, the third waveguide being located in the first layer of material; and

a fourth waveguide that is distinct and separate from the third waveguide, the fourth waveguide including a fourth multi-mode waveguide section and being located in the second layer of material;

the third multi-mode waveguide section is positioned adjacent to the fourth multi-mode waveguide section; and

a portion of the second waveguide is positioned adjacent to a portion of the third waveguide for coupling light from the second waveguide to the third waveguide.

13. The multi-channel multi-mode optical coupler of claim 12 , wherein:

the two or more multi-mode optical couplers also include a third multi-mode optical coupler and a fourth multi-mode optical coupler;

the third multi-mode optical coupler includes:

a fifth waveguide including a fifth multi-mode waveguide section, the fifth waveguide being located in the first layer of material; and

the fourth waveguide that is distinct and separate from the fifth waveguide, the fourth waveguide including a sixth multi-mode waveguide section that is different from the fourth multi-mode waveguide section;

the fifth multi-mode waveguide section is positioned adjacent to the sixth multi-mode waveguide section;

the fourth multi-mode optical coupler includes:

the first waveguide including a seventh multi-mode waveguide section that is different from the first multi-mode waveguide section; and

a sixth waveguide including an eighth multi-mode waveguide section, the sixth waveguide being located in the second layer of material;

the seventh multi-mode waveguide section is positioned adjacent to the eighth multi-mode waveguide section; and

a portion of the fifth waveguide is positioned adjacent to a portion of the sixth waveguide for coupling light from the fifth waveguide to the sixth waveguide.

14. A generalized Mach-Zehnder interferometer, comprising:

a first multi-channel optical coupler that includes four or more output ports;

a second multi-channel optical coupler that includes four or more input ports;

four or more optical waveguides, a respective optical waveguide of the four or more optical waveguides being connected to a respective output port of the four or more output ports and a respective input port of the four or more input ports; and

one or more phase shifters coupled with at least a subset of the four or more optical waveguides,

wherein one of the first multi-channel optical coupler and the second multi-channel optical coupler corresponds to the multi-channel multi-mode optical coupler of claim 13 .

15. A generalized Mach-Zehnder interferometer, comprising:

a first multi-channel optical coupler that includes four or more output ports;

a second multi-channel optical coupler that includes four or more input ports;

four or more optical waveguides, a respective optical waveguide of the four or more optical waveguides being connected to a respective output port of the four or more output ports and a respective input port of the four or more input ports; and

one or more phase shifters coupled with at least a subset of the four or more optical waveguides,

wherein: both the first multi-channel optical coupler and the second multi-channel optical coupler correspond to the multi-channel multi-mode optical coupler of claim 13 .

16. A method, comprising:

injecting first light into a first waveguide having a first multi-mode waveguide section, the first multi-mode waveguide section having a cross-section that is characterized by a first height and a first width that is greater than the first height such that the first light propagates in the first multi-mode waveguide section of the first waveguide in a fundamental mode;

transferring at least a portion of the first light from the first multi-mode waveguide section to a second multi-mode waveguide section of a second waveguide that is distinct and separate from the first waveguide, wherein:

the second multi-mode waveguide section has a cross-section characterized by a second height and a second width that is greater than the second height such that the transferred portion of the first light propagates in the second multi-mode waveguide section of the second waveguide in the fundamental mode;

the second multi-mode waveguide section of the second waveguide is positioned at least partially above or below the first multi-mode waveguide section of the first waveguide; and

the first multi-mode waveguide section and the second multi-mode waveguide section are separated by a first edge-to-edge distance; and

propagating the transferred portion of the first light.

17. The method of claim 16 , wherein:

the first waveguide includes a single-mode input waveguide section adiabatically coupled with the first multi-mode waveguide section; and

the method includes injecting the first light into the single-mode input waveguide section so that the first light propagates in the single-mode input waveguide section in the fundamental mode and the first light is coupled to the first multi-mode waveguide section while remaining in the fundamental mode.

18. The method of claim 17 , further comprising:

injecting second light into the second waveguide;

transferring at least a portion of the second light from the second multi-mode waveguide section to the first multi-mode waveguide section of the first waveguide; and

propagating the transferred portion of the second light through the first waveguide.

Continuity (4)

References Cited (63)