Wireless Josephson Amplifier Coupling for Low-Loss Qubit Readout
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Solution Overview
Problem
Integration of Josephson amplifiers into quantum electrodynamics systems is challenging due to the need for interconnects between different microwave environments, leading to losses and limited fidelity and tunability.
Innovation Solution
A wireless Josephson-junction-based amplifier is developed, using micro-antennas integrated onto a chip within a microwave waveguide, eliminating the need for physical electrical connections and reducing the number of ancillary components, thereby enhancing efficiency and tunability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional Josephson amplifiers use wire bonds and printed circuit boards to connect to microwave environments, then electrical connections are established, but signal losses increase and measurement fidelity decreases
Solution Approach 1:
The patent extracts and eliminates the wire bonds and printed circuit board interconnects from the system by implementing a wireless coupling mechanism using evanescent electromagnetic fields. The Josephson amplifier is directly coupled to the waveguide through near-field interaction, removing the intermediate transmission media that cause signal losses.
Solution Approach 2:
The patent introduces evanescent electromagnetic fields as an intermediary medium to transfer signals between the Josephson amplifier and the waveguide without physical wire connections. This field-based intermediary enables wireless coupling while maintaining signal integrity and avoiding the losses associated with traditional conductive interconnects.
2Adaptability or versatility
If conventional Josephson amplifiers use multiple ancillary microwave components like directional couplers and hybrids, then the amplifier can operate, but the system complexity increases and tunability is limited
Solution Approach 1:
The patent removes ancillary microwave components such as directional couplers and hybrids from the system by implementing direct wireless coupling between the Josephson amplifier and the waveguide. This extraction simplifies the system architecture while maintaining full operational capability through evanescent field interaction.
Solution Approach 2:
The Josephson amplifier is designed to perform multiple functions directly without requiring separate ancillary components. The wireless coupling mechanism enables the amplifier to simultaneously achieve signal amplification, impedance matching, and tunability through a single integrated structure, reducing the overall component count.
3Reliability
If wire bonds and transitions between different microwave environments are used, then electrical connectivity is achieved, but impedance complexity increases and amplifier performance is limited
Solution Approach 1:
The patent extracts the complex impedance transformation network (wire bonds, transitions, and matching components) by implementing direct wireless coupling. The evanescent field interaction provides natural impedance matching between the Josephson amplifier and the waveguide, eliminating the need for complex impedance transformation structures.
4Measurement precision
If conventional amplifiers use physical electrical connections to transmit signals, then signal transmission is established, but measurement efficiency and fidelity are reduced
Solution Approach 1:
The patent extracts the lossy physical interconnects (wire bonds and printed circuit traces) and replaces them with wireless evanescent field coupling. This eliminates the primary sources of signal loss and thermal noise in the signal path, thereby improving qubit readout fidelity and measurement precision.
Solution Approach 2:
Evanescent electromagnetic fields serve as a low-loss intermediary medium for signal transmission between the Josephson amplifier and the waveguide. This field-based transmission path introduces minimal loss and thermal noise compared to conductive interconnects, preserving signal integrity and improving measurement fidelity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The wireless amplifier maintains gain and bandwidth performance while improving dynamic range and reducing noise, making it suitable for scalable quantum information processing systems.
Implementation Method 1
Josephson-junction-based amplifiers for detection and processing of qubits
Implementation Method 2
Interaction of the amplifier with the microwave environment is achieved wirelessly by one or more micro-antennas integrated onto a chip
Data Source
AI summary
A wireless Josephson-junction-based amplifier is described that provides improved tunability and increased control over both a quality factor Q and participation ratio p of the amplifier. The device may be fabricated on a chip and mounted in a waveguide. No wire bonding between the amplifier and coaxial cables or a printed circuit board is needed. At least one antenna on the chip may be used to couple energy between the waveguide and wireless JBA. The amplifier is capable of gains greater than 25 dB.