RF Circuit Design for Quantum Computing

The lab is currently a part of a project that will realize cryogenic circuits for control and readout of qubit signals and states. An area that our lab focuses on is setting up the system for qubit readout, using methods such as dispersive readout methods, while combining with components like Purcell filters, amplifiers (TWPAs and cryo-CMOS LNAs), and FPGAs and ADCs to successfully obtain the readout signal. Research is being done on setting up the hardware system in the dilution fridge, as well as designing the individual components that are needed for readout. 

Researcher: Ian Huang (黃慕召) and Swin Tan (陳士允)

Cryogenic Low-Noise Amplifiers (LNAs) are critical components in RF circuits for quantum computing, amplifying weak signals from quantum devices while minimizing the introduction of noise. In quantum computing systems, maintaining signal integrity is paramount, as noise can disrupt quantum states and interfere with computations. This research focuses on the design of a high-gain, low-noise LNA for application in the superconducting quantum circuits developed by other graduate students in our lab. 

Researcher: Wei-Lun Lo (羅偉倫)

Our lab specializes in the design of cryogenic CMOS LNAs operating at 4K temperatures for the reflectometry readout of spin qubits and the dispersive readout of superconducting qubits. 

Researcher: Swin Tan (陳士允)

A key focus of our research is the development of cryogenic sample holders and packages for housing qubits and device chips within a dilution refrigerator. This necessitates the selection of components with cryogenic durability and packaging materials that preserve qubit coherence. Additionally, our design considerations encompass effective thermal anchoring, ensuring microwave signal integrity, optimizing scalable packaging configurations, and implementing robust shielding against magnetic and other potential interferences. 

Researcher: Swin Tan (陳士允)

Accurate characterization of cryogenic device and circuit performance is crucial for advancing quantum computing technology. Our lab is developing a cryogenic S-parameter measurement and calibration system operating at millikelvin temperatures. This system prioritizes improved precision and reduced size through optimized design. To minimize calibration uncertainties, a broadband cryogenic CMOS switch is proposed as a key component. The design and implementation of this critical component are currently under active research. 

Researcher: Swin Tan (陳士允) and Ian Huang (黃慕召)