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Cascaded low-pass filters for the measurements of DC characteristics of superconducting qubits

Tie Li

Cascaded low-pass filters are designed and fabricated for the measurements of dc characteristics of superconducting qubits. The filters are cascaded by LCR filter and copper powder filter. At 77 K the cutoff frequency is 120 kHz and the roll-off is -40 dB/decade. We achieved an attenuation -60 dB when the frequency is above 10 MHz. The frequency response of the cascaded filters is better than single LCR filter or copper powder filter and high frequency noise can be suppressed effectively at low temperature.Cascaded low-pass filters are designed and fabricated for the measurements of dc characteristics of superconducting qubits. The filters are cascaded by LCR filter and copper powder filter. At 77 K the cutoff frequency is 120 kHz and the roll-off is -40 dB/decade. We achieved an attenuation -60 dB when the frequency is above 10 MHz. The frequency response of the cascaded filters is better than single LCR filter or copper powder filter and high frequency noise can be suppressed effectively at low temperature.

Chinese Science BulletinJan 1, 20100 citations

Carbon-Nanotube-Based Microwave Filters for Superconducting Qubit Measurements

Mehran Vahdani Moghaddam, C. W. Sandbo Chang, Ibrahim Nsanzineza +2 more

Bulletin of the American Physical SocietyMar 9, 20180 citations

Robust cryogenic matched low-pass coaxial filters for quantum computing applications

Аnton I. Ivanov, Victor I. Polozov, Vladimir V. Echeistov +5 more

Electromagnetic noise is one of the main external factors decreasing superconducting qubit coherence. Matched coaxial filters can prevent microwave and IR photons' negative influence on superconducting quantum circuits. In this report, we describe the design and fabrication process of matched coaxial filters for noise-sensitive measurements at millikelvin temperatures. A robust transmission coefficient and ultralow reflection loss of −20 dB in the frequency range up to 20 GHz is achieved. Fabricated low-pass filters have linear transmission and reflection characteristics with 3 dB-cutoff frequency of 1.5–2.5 GHz. A method for extracting the propagation constant and filter impedance from scattering parameter measurements is demonstrated. This method is experimentally approved on a filter with a compound of Cu powder and Stycast epoxy resin and a filter filled with ECCOSORB CR-110 epoxy resin. The proposed design and assembly technology are versatile for various compounds and provide highly repeatable geometric and microwave characteristics. Furthermore, we demonstrate that these low-pass coaxial filters can be effectively utilized to improve superconducting qubit relaxation due to suppressing standing waves originating from reflections in control coaxial cables.Electromagnetic noise is one of the main external factors decreasing superconducting qubit coherence. Matched coaxial filters can prevent microwave and IR photons' negative influence on superconducting quantum circuits. In this report, we describe the design and fabrication process of matched coaxial filters for noise-sensitive measurements at millikelvin temperatures. A robust transmission coefficient and ultralow reflection loss of −20 dB in the frequency range up to 20 GHz is achieved. Fabricated low-pass filters have linear transmission and reflection characteristics with 3 dB-cutoff frequency of 1.5–2.5 GHz. A method for extracting the propagation constant and filter impedance from scattering parameter measurements is demonstrated. This method is experimentally approved on a filter with a compound of Cu powder and Stycast epoxy resin and a filter filled with ECCOSORB CR-110 epoxy resin. The proposed design and assembly technology are versatile for various compounds and provide highly repeatable geometric and microwave characteristics. Furthermore, we demonstrate that these low-pass coaxial filters can be effectively utilized to improve superconducting qubit relaxation due to suppressing standing waves originating from reflections in control coaxial cables.

Applied Physics LettersNov 13, 202311 citations

Design of a Cryogenic, Digital Measurement Circuit for Superconducting Qubits

Caleb Howington, Alexander Opremcak, Alex F. Kirichenko +3 more

Bulletin of the American Physical SocietyMar 5, 20190 citations

Nonlinear dissipative filters for measurement protection on superconducting qubits

P. Forn-Díaz, Raymond N. Schouten, Kees Harmans +1 more

Bulletin of the American Physical SocietyMar 17, 20090 citations

Generation of a sub-Poissonian state with quantum high- and low-pass filters

Haibo Wang, Yongmin Li, Satoru Odate +1 more

We introduce a quantum component, the quantum high- and low-pass filter, and analyze its output characteristic. It is shown that a quantum bandpass filter can be achieved by using passive linear optics and projection measurements. Furthermore, we show that the sub-Poissonian state can be generated by using a cascaded quantum low-pass filter and high-pass filter.

Physical Review AJul 27, 20051 citation

Cascaded low-pass filters for the measurements of DC characteristics of superconducting qubits

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Cascaded low-pass filters for the measurements of DC characteristics of superconducting qubits

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