US-20260128195-A1 - Tapered Connectors for Superconductor Circuits

Abstract

The various embodiments described herein include methods, devices, and circuits for reducing or minimizing current crowding effects in manufactured superconductors. In some embodiments, a superconducting circuit includes: (i) a first component; (ii) a second component; (iii) a third component; and (iv) a superconducting connector electrically connecting the first component, the second component, and the third component, the connector including a first section that splits at a splitting end into a second section and a third section. The first section connecting to the first component at a first end and widening in accordance with an electrical current streamline prior to the splitting end.

Inventors

• Brad A.J. Moores
• Faraz Najafi

Assignees

• PsiQuantum Corp.

Dates

Publication Date

20260507

Application Date

20241108

Claims (19)

1. 1 . A superconducting circuit, comprising: a first component; a second component; a third component; and a superconducting connector electrically connecting the first component, the second component, and the third component, the connector comprising a first section that splits at a splitting end into a second section and a third section; wherein the first section connects to the first component at a first end; wherein the first section widens prior to the splitting end; and wherein the first section widens in accordance with an electrical current streamline.
2. 2 . The superconducting circuit of claim 1 , wherein the second section tapers from a first width at the split end.
3. 3 . The superconducting circuit of claim 2 , wherein the second section tapers in accordance with an electrical current streamline.
4. 4 . The superconducting circuit of claim 2 , wherein the taper has a non-linear slope.
5. 5 . The superconducting circuit of claim 2 , wherein a slope of the taper of the second section matches a slope of the widening of the first section at a connection point between the first section and the second section.
6. 6 . The superconducting circuit of claim 5 , wherein an edge of the superconducting connector has a continuous first derivative over the length of the edge of the superconducting connector.
7. 7 . The superconducting circuit of claim 1 , wherein the first section has a maximum width at the splitting end.
8. 8 . The superconducting circuit of claim 1 , wherein the first section widens with a non-linear slope.
9. 9 . The superconducting circuit of claim 1 , wherein the first section widens to reduce current crowding at the splitting end.
10. 10 . The superconducting circuit of claim 1 , wherein at least one of the first component, the second component, and the third component comprises a superconducting component.
11. 11 . The superconducting circuit of claim 1 , wherein at least one of the first component, the second component, and the third component comprises a via or contact pad.
12. 12 . A method of generating superconducting connectors, the method comprising: setting a shape for a superconducting connector having a feature, the shape including a first edge contour for the feature; identifying one or more hot spots and a plurality of current streamlines in the superconducting connector by simulating current flow through the superconducting connector; selecting a first streamline of the plurality of current streamlines, the first streamline being adjacent to at least one hot spot of the one or more hot spots; and adjusting the shape for the superconducting connector to have a second edge contour for the feature, the second edge contour shaped in accordance with the first streamline.
13. 13 . The method of claim 12 , wherein the first streamline bounds the at least one hot spot.
14. 14 . The method of claim 12 , further comprising repeating the identifying, selecting, and adjusting until simulating current flow through the superconducting connector does not identify a hot spot.
15. 15 . The method of claim 12 , wherein the feature comprises a bend in the superconducting connector.
16. 16 . The method of claim 12 , wherein the feature comprises a split in the superconducting connector.
17. 17 . The method of claim 16 , wherein the feature further comprises a widening of the superconducting connector prior to the split, wherein the first edge contour corresponds to the widening.
18. 18 . The method of claim 17 , wherein the feature further comprises a tapering of the superconducting connector after the split.
19. 19 . The method of claim 12 , wherein the first edge contour has a linear slope and the second edge contour has a non-linear slope.

Description

RELATED APPLICATIONS This application is a continuation of PCT Patent Application Serial No. PCT/US2023/021568, filed May 9, 2023, which claims the benefit of and priority to U.S. Provisional Patent Application No. 63/340,392, filed May 10, 2022, each of which is incorporated by reference herein in its entirety. TECHNICAL FIELD This relates generally to superconducting circuits, including but not limited to, tapered connectors for superconducting circuits. BACKGROUND Superconductors are materials capable of operating in a superconducting state with zero electrical resistance under particular conditions. One parameter for operating in a superconducting state is current density. If current density exceeds a superconducting density threshold the superconductor will operate in a non-superconducting state. Geometric shapes such as corners may lead to current crowding effects that result in the current density exceeding the superconducting density threshold at some locations. SUMMARY Geometric shapes, such as bends, corners, and splits, in a superconducting circuit can result in current crowding effects if not constructed appropriately. The current crowding effects can cause the superconducting circuit to operate a non-superconducting state, which may result in operational failures and erroneous results. A mathematically-optimal geometry can be calculated for some standard shapes, such as 90-degree turn or a 180-degree turn. However, in some circumstances these standard shapes are insufficient to construct a larger superconducting circuit or system. For example, sizing and layout requirements of the superconducting circuit or system may require a superconducting connector to split; or require the superconducting connector to have a non-standard turn angle. In accordance with some embodiments, an iterative process is used for designing a superconducting connector having a geometric shape such as a bend, corner, or split. For example, an initial boundary is selected for the connector (e.g., having a constant width). Then current is simulated through the connector to identify any current crowding locations (e.g., locations where the current density exceeds a superconducting density threshold). To continue the example, a current streamline from the simulation is used to generate an updated boundary for the connector (e.g., having an increased width in proximity to the bend, corner, or split). In accordance with some embodiments, the simulation and selection of an updated boundary is repeated until the simulation results show no current crowding locations. This iterative process allows for the construction of connectors that have a reduced or minimized area as compared to connectors with only standard shapes. In some circumstances, the reduced area results in more accurate superconducting circuitry that is less susceptible to errors introduced by errant photons being absorbed by the superconducting circuitry and connectors. In addition to making more compact superconducting circuits and systems, this process allows for construction of connectors that are more tolerant to variations introduced by a fabrication process (e.g., lithography). Accordingly, in one aspect, some embodiments include a superconducting circuit having a first component, a second component, a third component, and a superconducting connector electrically connecting the first component, the second component, and the third component, the connector including a first section that splits at a splitting end into a second section and a third section; where the first section connects to the first component at a first end; where the first section widens (e.g., tapers outward) prior to the splitting end; and where the first section widens in accordance with an electrical current streamline. In another aspect, some embodiments include a method of generating (e.g., designing) superconducting connectors. The method includes: (i) setting a shape for a superconducting connector having a feature, the shape including a first edge contour for the feature; (ii) identifying one or more hot spots and a plurality of current streamlines in the superconducting connector by simulating current flow through the superconducting connector; (iii) selecting a first streamline of the plurality of streamlines, the first streamline being adjacent to at least one hot spot of the one or more hot spots; and (iv) adjusting the shape for the superconducting connector to have a second edge contour for the feature, the second edge contour shaped in accordance with the first streamline. Thus, devices and circuits are provided with methods for reducing or minimizing current crowding by use of tapered connectors, thereby increasing the effectiveness, efficiency, and user satisfaction with such circuits and devices. Such circuits, devices, and methods optionally complement or replace conventional devices, circuits, and methods for reducing or minimizing current crowding effects. BRIEF DESCRIPT