A Compact Broadband Purcell Filter for Superconducting Quantum Circuits in a 3D Flip-Chip Architecture

Fuente: arXiv
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Main Authors: Luo, Zhen, Richard, Lea, Tsitsilin, Ivan, Bhattacharjee, Anirban, Schneider, Christian M. F., Filipp, Stefan, Hagelauer, Amelie
Format: Preprint
Published: 2026
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author Luo, Zhen
Richard, Lea
Tsitsilin, Ivan
Bhattacharjee, Anirban
Schneider, Christian M. F.
Filipp, Stefan
Hagelauer, Amelie
author_facet Luo, Zhen
Richard, Lea
Tsitsilin, Ivan
Bhattacharjee, Anirban
Schneider, Christian M. F.
Filipp, Stefan
Hagelauer, Amelie
contents Fast and high-fidelity qubit readout requires strong coupling between the readout resonator and the feedline. However, such coupling unavoidably enhances qubit decay through the Purcell effect. We present a four-pole broadband Purcell filter implemented on a 3D flip-chip platform to overcome this trade-off. The filter provides a flat 1 GHz passband centered at 7.68 GHz and achieves more than 45 dB suppression at typical qubit frequencies. We demonstrate the filter's compatibility with multiplexed readout using a test chip that integrates six floating readout resonators strongly coupled within the passband. The chip is fabricated using a 150 nm Niobium (Nb) thin-film process and characterized at 20 mK in a cryogenic measurement setup. We also develop an analytical model that accurately captures the filter response and determines the resonance frequencies and external quality factors of the floating resonators directly from their physical geometry, enabling rapid circuit synthesis and design optimization. The proposed design is compact and fabrication-tolerant, making it a practical solution for large-scale superconducting quantum processors.
format Preprint
id arxiv_https___arxiv_org_abs_2603_16693
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Compact Broadband Purcell Filter for Superconducting Quantum Circuits in a 3D Flip-Chip Architecture
Luo, Zhen
Richard, Lea
Tsitsilin, Ivan
Bhattacharjee, Anirban
Schneider, Christian M. F.
Filipp, Stefan
Hagelauer, Amelie
Quantum Physics
Fast and high-fidelity qubit readout requires strong coupling between the readout resonator and the feedline. However, such coupling unavoidably enhances qubit decay through the Purcell effect. We present a four-pole broadband Purcell filter implemented on a 3D flip-chip platform to overcome this trade-off. The filter provides a flat 1 GHz passband centered at 7.68 GHz and achieves more than 45 dB suppression at typical qubit frequencies. We demonstrate the filter's compatibility with multiplexed readout using a test chip that integrates six floating readout resonators strongly coupled within the passband. The chip is fabricated using a 150 nm Niobium (Nb) thin-film process and characterized at 20 mK in a cryogenic measurement setup. We also develop an analytical model that accurately captures the filter response and determines the resonance frequencies and external quality factors of the floating resonators directly from their physical geometry, enabling rapid circuit synthesis and design optimization. The proposed design is compact and fabrication-tolerant, making it a practical solution for large-scale superconducting quantum processors.
title A Compact Broadband Purcell Filter for Superconducting Quantum Circuits in a 3D Flip-Chip Architecture
topic Quantum Physics
url https://arxiv.org/abs/2603.16693