TLS Thermometer Resonator Frequency Shift for Cryogenic Temperature
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Solution Overview
Problem
Resistance-based thermometers used in cryogenic quantum computing devices face challenges such as complexity, electromagnetic interference, and inaccurate temperature readings due to excessive wiring, making it difficult to measure on-chip temperatures effectively.
Innovation Solution
A Two-Level System (TLS) thermometer that uses a superconducting micro-resonator with amorphous dielectric materials to measure temperature by correlating resonance frequency shifts with temperature, eliminating the need for dedicated wiring and allowing for real-time monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistance-based thermometers are used to measure temperature, then temperature measurement is achieved, but device complexity increases due to excessive wiring requirements
Solution Approach 1:
The patent extracts the temperature sensing function from a separate wired thermometer and integrates it directly into the microwave device chip. The TLS thermometer is formed by depositing dielectric materials containing two-level systems directly on the chip substrate, eliminating the need for separate resistance-based thermometer wires and their complex routing to room temperature electronics.
Solution Approach 2:
The microwave device feedline serves dual purposes: it both transmits microwave signals for device operation and carries the temperature measurement function through the TLS resonator coupled to the same feedline. This multi-functionality eliminates dedicated thermometer wires while maintaining temperature measurement capability.
2Measurement precision
If dedicated wires are routed for resistance-based thermometers, then temperature reading is obtained, but electromagnetic interference is introduced
Solution Approach 1:
The temperature measurement function is merged with the existing microwave feedline structure. The TLS resonator is capacitively coupled to the feedline, allowing the same microwave transmission path to also serve as the temperature sensing channel, thereby eliminating separate wires that would introduce electromagnetic interference.
3Measurement precision
If resistive thermometers are used, then temperature measurement is possible, but thermal load increases heating the microwave device
Solution Approach 1:
The patent replaces the electrical resistance-based measurement system with a microwave resonant frequency-based system. Instead of measuring electrical resistance through current-carrying wires that conduct thermal energy, the system measures the resonant frequency of TLS transitions excited by microwave fields, which do not carry significant thermal load.
4Measurement precision
If resistance-based thermometers are integrated, then on-chip temperature measurement is achieved, but integration difficulty increases
Solution Approach 1:
The TLS thermometer is segmented into distinct functional layers deposited directly on the chip: a first dielectric layer containing TLS formed during chip fabrication, and a second dielectric layer deposited afterward. This segmentation allows the thermometer to be integrated into existing chip manufacturing processes without requiring post-fabrication wire bonding or complex assembly.
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 TLS thermometer provides accurate, real-time on-chip temperature measurements with a faster response time compared to conventional resistive thermometers, reducing electromagnetic interference and thermal load, and can be easily integrated into cryogenic microwave devices without additional infrastructure.
Implementation Method 1
The resonance frequency of the lumped-element resonator device is sensitive to the temperature. The lumped-element resonance device interacts with the probe signal and modulates the phase and amplitude of the probe signal.
Implementation Method 2
A Two-Level System (TLS) thermometer 100 measures temperatures below 1 Kelvin. The TLS thermometer 100 comprises a superconducting micro-resonator with amorphous dielectric materials. The dielectric materials comprise TLSs grown, deposited or naturally formed on the surfaces.
Data Source
AI summary
Technology is disclosed herein that the enhances the measurability of on-chip temperature in a cryogenic quantum computing environment. In an implementation, transceiver circuitry sends a probe signal through a target device. A lumped-element resonator device that is proximate to the surface of the target device interacts with the probe signal and modulates the probe signal. Processing circuitry reads the probe signal through the target device, and responsively measures the resonance frequency of the lumped-element resonator device. The processing circuitry correlates the measured resonance frequency with a temperature and responsively determines the temperature of the target device.