Systems, methods, and apparatus for reducing crossover coupling of two or more RF signals are described. In one case, a crossover structure is described where RF signals are routed through coplanar waveguides having a specific characteristic impedance and crossing at a central point of the crossover structure by way of a bridge. A ground shield having a geometry adapted to reduce the crossover coupling while minimally affecting capacitive coupling between the RF signals and the ground shield is introduced in-between a region comprising the central point. Further described is a multi-port rotary RF switch fitted with the crossover structure which allows substantially balanced electrical performance across all the operational states of the rotary RF switch at RF signal frequencies up to 40 GHz and beyond.

A transformer balun fabricated in silicon and including a series of alternating metal layers and dielectric layers that define first and second outer conductors that are part of a coaxial structure. Each dielectric layer includes a plurality of conductive vias extending through the dielectric layer to provide electrical contact between opposing metal layers, where a top metal layer forms a top wall of each outer conductor and a bottom metal layer forms a bottom wall of each outer conductor and the other metal layers and the dielectric layers define sidewalls of the outer conductors. Inner conductors extends down both of the first and second outer conductors and a first output line is electrically coupled to a sidewall of the first outer conductor and a second output line is electrically coupled to a sidewall of the second outer conductor.

According to an example aspect of the present invention, there is provided a travelling wave parametric amplifier comprising a waveguide transmission line comprising therein at least ten Josephson elements, wherein each of the at least ten Josephson element comprises a loop, with exactly one Josephson junction of first size on one half of the loop and at least two Josephson junctions of a second size on a second half of the loop, the second size being larger than the first size, a flux bias line configured to generate a magnetic flux threading each of the at least one loop, and a set of resistors coupled with the flux bias line.

In a described example, an apparatus includes a package substrate having a device side surface and a board side surface opposite the device side surface, a physics cell mounted on the device side surface having a first end and a second end, a first opening extending through the package substrate and lined with a conductor, aligned with the first end, a second opening extending through the package substrate and lined with the conductor, aligned with the second end, a millimeter wave transmitter module on the board side, having a millimeter wave transfer structure including a transmission line coupled to an antenna aligned with the first opening, and a millimeter wave receiver module mounted on the board side surface of the package substrate and having a millimeter wave transfer structure including a transmission line coupled to an antenna for receiving millimeter wave signals, aligned with the second opening.

Devices and/or computer-implemented methods facilitating static ZZ suppression and Purcell loss reduction using mode-selective coupling in two junction superconducting qubits are provided. In an embodiment, a device can comprise a superconducting bus resonator. The device can further comprise a first superconducting qubit. The device can further comprise a second superconducting qubit, the first superconducting qubit and the second superconducting qubit respectively comprising: a first superconducting pad; a second superconducting pad; a third superconducting pad; a first Josephson Junction coupled to the first superconducting pad and the second superconducting pad; and a second Josephson Junction coupled to the second superconducting pad and the third superconducting pad. The first superconducting pad and the second superconducting pad of the first superconducting qubit and the second superconducting qubit are coupled to the superconducting bus resonator. The superconducting bus resonator entangles the first superconducting qubit and the second superconducting qubit based on receiving a control signal.

A circuit board includes a dielectric substrate, a signal line and a pair of ground wires. The dielectric substrate includes a base and an elevated platform protruding from an upper surface of the base. The signal line is conformally disposed on the dielectric substrate and includes a first segment disposed on an upper surface of the elevated platform, a second segment extending on the upper surface of the base, and a third segment disposed on a sidewall of the elevated platform and connecting the first segment and the second segment. The pair of ground wires are disposed on the dielectric substrate and are spaced apart from the signal line. A projection of the second segment of the signal line on the upper surface of the base partly overlaps projections of the pair of ground wires on the upper surface of the base.

A system that includes: an array of qubits, each qubit of the array of qubits comprising a first electrode corresponding to a first node and a second electrode corresponding to a second node, wherein, for a first qubit in the array of qubits, the first qubit is positioned relative to a second qubit in the array of qubits such that a charge present on the first qubit induces a same charge on each of the first node of the second qubit and the second node of the second qubit, such that coupling between the first qubit and the second qubit is reduced, and wherein none of the nodes share a common ground is disclosed.

A wafer-level manufacturing method for embedding a passive element in a glass substrate is disclosed. A highly doped silicon wafer is dry etched to form a highly doped silicon mould wafer, containing highly doped silicon passive component structures mould seated in cavity arrays; a glass wafer is anodically bonded to the highly doped silicon mould wafer in vacuum pressure to seal the cavity arrays; the bonded wafers are heated so that the glass melts and fills gaps in the cavity arrays, annealing and cooling are performed, and a reflowed wafer is formed; the upper glass substrate of the reflowed wafer is grinded and polished to expose the highly doped silicon passives; the passive component structure mould embedded in the glass substrate is fully etched; the blind holes formed in the glass substrates after the passive component structure mould has been etched is filled with copper by electroplating; the highly doped silicon substrate and unetched silicon between the cavity arrays are etched, and several glass substrates embedded with a passive element are obtained; to form electrodes for the passives, a metal adhesion layer is deposited, and a metal conductive layer is electroplated. The process is simple, costs are low, and the prepared passive elements have superior performance.

A parametric traveling wave amplifier (200) is disclosed in which the amplifiers include: a co-planar waveguide, in which the co-planar waveguide includes at least one Josephson junction (210) interrupting a center trace (204) of the co-planar waveguide; and at least one shunt capacitor coupled to the co-planar waveguide, in which each shunt capacitor of the at least one shunt capacitor includes a corresponding superconductor trace (214) extending over an upper surface of the center trace of the co-planar waveguide, and in which a gap separates the superconductor trace from the upper surface of the center trace, and in which the co-planar waveguide including the at least one Josephson junction and the shunt capacitor establish a predefined overall impedance for the traveling wave parametric amplifier.

A non-reciprocal device using a space-time modulation scheme. By applying the space-time modulation scheme, reciprocity in radiation and scattering scenarios is prevented. Such a scheme utilizes a linear system with simple, compact and inexpensive electronic components compared to the current use of bulky duplexers and non-reciprocal magnet based phase shifters to provide non-reciprocity. One such linear system involves traveling-wave antennas loaded with voltage dependent capacitors that are modulated in space and time thereby allowing the antenna to transmit with high directivity in a certain direction and not receive from that direction. Another linear system involves a resonant metasurface characterized by transverse spatiotemporal gradients, where the spatiotemporal gradients include periodically modulated impedances thereby causing a non-reciprocal transmission response. In this manner, a signal that propagates and impinges on the surface at a given direction will be fully transmitted while a signal propagating from the complementary direction will be fully reflected.