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Electronics Letters

A fully integrated nanosecond burst RF generator for quantum technologies

Carlos Sánchez‐Azqueta, C. Aldea, Santiago Celma

Published Jan 1, 2024• 3 citations
Publisher

Abstract

Abstract Quantum technologies is an emerging field of physics and engineering based on exploiting properties of quantum mechanics such as entanglement, superposition, or tunneling, and which is expected to impact many applications, such as communications, simulation, computation, or sensing and metrology. The operation of quantum technologies is based on the manipulation of the quantum states of certain devices, either to induce transitions between states or to detect the transitions. Irrespective of the practical realization of these quantum devices, their manipulation requires interacting with their quantum resonant states, for which very narrow radio‐frequency (RF) bursts in the range of the GHz are required. Arbitrary waveform generators are used to generate these signals for test purposes, but this is not suitable for practical quantum technology applications, which will need to produce the required bursts by specific circuit building blocks with low power and small dimensions. Here, an integrated RF burst generator capable of producing GHz bursts shorter than 1 ns is presented. The proposed architecture is tested using a 5 GHz quadrature LC‐tank voltage‐controlled oscillator (LC‐VCO), showing that the four equally spaced phases can be switched every 500 ps, which allows the generation of more complex RF bursts for optimized quantum state manipulation.

DOI
10.1049/ell2.13016

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Superconducting qubits are the promising candidate to realize large-scale quantum computing systems. Well-known quantum algorithms, such as Shor's algorithm, require at least10510^{5}105to10610^{6}106qubits to execute. Accordingly, classical systems for controlling superconducting qubits must also be scalable. One critical scalability challenge lies in the circuit cost of an RF pulse generator used to implement quantum gate operations. This poster proposes a cost-effective architecture for an RF pulse generator tailored to superconducting qubits. Most existing works use arbitrary waveform generators (AWGs) that require both a high-bandwidth memory (HBM) and a high-performance digital-analog converter (DAC) to achieve the highest gate fidelity with an optimized RF pulse waveform. The proposed pulse generator architecture significantly simplifies both the generator circuit and the waveform of the RF pulse to cost-aware square pulses. This architecture eliminates the requirement for power- and cost-intensive AWG, which is a major obstacle in realizing scalable quantum computers. Additionally, this poster demonstrates that our architecture can mitigate the error source associated with simplified RF pulses. Quantum dynamics simulation of transmon qubits, wherein the state of the system evolves with time, demonstrates that our pulse generator can achieve practically the same fidelity of gate operations for single and multiple qubits as ideal RF pulses while substantially reducing the sampling rate of DACs and the bandwidth of memories.