Superconducting Quantum Chip Bonding Structure for Low-Loss Coupling
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Solution Overview
Problem
Current superconducting quantum chip connection technologies suffer from high channel loss and low quality factors due to the use of niobium-titanium alloy coaxial lines and crimping connections, leading to weak capacitive coupling and significant energy loss at the bonding interface.
Innovation Solution
A connection structure and method utilizing aluminum coaxial cables and coplanar waveguide transmission lines to minimize channel loss and energy loss, featuring a current conversion portion that ensures standing wave current at the bonding interface is close to zero, and a coupler to control coupling strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If niobium-titanium alloy coaxial lines are used for connection, then superconducting quantum chips can be interconnected, but channel loss is high and quality factor is low (5.1×10^4)
Solution Approach 1:
The patent changes the material parameter from niobium-titanium alloy to aluminum, and changes the connection method parameter from crimping to bonding with current conversion. This material and method parameter change increases the quality factor from 5.1×10^4 to over 1.2×10^6 while reducing channel loss, directly resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The patent replaces the mechanical crimping connection system with a bonding connection system that includes a current conversion portion. This substitution eliminates the mechanical contact resistance issue and achieves stronger coupling with lower energy loss, resolving the contradiction between connection reliability and energy loss at the interface.
2Reliability
If crimping connections are used, then superconducting quantum chips can be connected, but capacitive coupling is weak (around 1 MHz) and contact resistance causes energy loss
Solution Approach 1:
The patent introduces a current conversion portion as an intermediary component between the quantum circuit and the connection portion. This intermediary converts the current distribution and ensures that the standing wave current at the bonding interface is close to zero, thereby eliminating contact resistance losses and strengthening capacitive coupling, directly resolving the contradiction between coupling strength and energy loss.
3Productivity
If multiple superconducting quantum chips are connected in modular way, then more quantum bits can be integrated, but channel loss increases and decoherence risk increases
Solution Approach 1:
The patent divides the large-scale quantum processor into multiple modular superconducting quantum chips that can be connected together. By using the aluminum-based connection structure with current conversion for each module interface, the segmentation enables scalable quantum bit integration while the low-loss connection method prevents channel loss from increasing with the number of modules, resolving the contradiction between productivity and energy loss.
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 proposed solution achieves an intrinsic quality factor of 1.2×106, significantly reducing channel loss and energy loss, enabling stronger coupling and improving quantum state transmission fidelity to over 99% across chips.
Implementation Method 1
Both the inner and outer conductor layers are made of pure aluminum or aluminum alloy... an intrinsic quality factor of 1.2×10^6... significantly reducing channel loss
Implementation Method 2
The connection portion further employs a coplanar waveguide transmission line, which is situated on the superconducting quantum chips and comprises metal conductor strips and ground conductor strips
Implementation Method 3
ensuring that the standing wave current of the communication standing wave mode at the bonding connection interface is close to zero
Implementation Method 4
bond the quantum circuits and the connection portion, ensuring that the standing wave current of the communication standing wave mode at the bonding connection interface is close to zero
Data Source
AI summary
The present disclosure relates to a superconducting quantum chip connection structure used for connecting between superconducting quantum chips. The superconducting quantum chips comprise quantum substrates and quantum circuits. The connection structure includes: a connection portion for connecting the superconducting quantum chips; and a current conversion portion disposed on the quantum substrate for bonding and connecting the quantum circuits to the connection portion, so that the standing wave current of the standing wave mode used for communication at the bonding connection interface is close to zero. The present disclosure can not only significantly reduce channel loss and achieve stronger coupling, but also significantly reduce energy loss at the bonding connection interface, thereby reducing the impact on quantum state transmission efficiency.