A Cryo-CMOS Wideband Quadrature Receiver With Frequency Synthesizer for Scalable Multiplexed Readout of Silicon Spin Qubits

Abstract

In this article, a cryo-CMOS receiver integrated with a frequency synthesizer for scalable multiplexed readout of qubits is presented, focusing on radio frequency (RF) reflectometry readout of silicon-based semiconductor spin qubits/quantum dots. The proposed spin qubit readout chip consists of a wideband low noise amplifier (LNA), a quadrature mixer, a complex filter, a pair of in-phase/quadrature (I/Q) intermediate frequency (IF) amplifier chains, and a type-II charge-pump phase-locked loop (PLL) with a programmable frequency divider providing local oscillator (LO) signals. Noise optimizations are applied to the LNA design and the quadrature active mixer design to obtain the required performance. A mode-switching complementary voltage-controlled oscillator (VCO) is proposed to achieve low-power and low-phase noise in a wide-frequency tuning range (46.5%). Circuit modifications and design considerations for robust cryogenic temperature operation are presented and discussed. Measurements show that the receiver provides an average gain of 65 dB, a minimum noise figure of 0.5 dB, an IF bandwidth of 0.1-1.5 GHz, and an image rejection ratio of 23 dB at 3.5 K with a power consumption of 108 mW. This cryo-CMOS receiver with frequency synthesizer for spin qubit readout is a first step toward fully-integrated qubit readout and control.

Silicon spin qubits from laboratory to industry

“…This cryo-CMOS receiver with frequency synthesizer for qubit readout is a first step towards fully-integrated qubit readout and control. Figure 14 shows a micrograph of the readout chip Quadro with the overall specifications that can be found in [215].…”

“…Photomicrograph of the chip Quadro. The chip's specifications and measurements can be found in[215]. Reproduced from[215].…”

A 40-nm Cryo-CMOS Quantum Controller IC for Superconducting Qubit

“…It includes multiple phase-locked loops (PLLs) for the internal generation of LOs. There has been previous demonstration on including a PLL for internal LO generation for the readout of spin qubits with FDM [25]. This work proposes employing multiple PLLs, which enables managing different LO frequencies with each PLL responsible for one LO frequency for a group of qubits, where the group can be selected out of thousands or millions of qubits.…”