| AVS 65th International Symposium & Exhibition | |
| Materials and Processes for Quantum Computing Focus Topic | Monday Sessions |
| Session MP+AM+EM+NS-MoA |
| Session: | Systems and Devices for Quantum Computing II |
| Presenter: | Xian Wu, National Institute of Standards and Technology |
| Authors: | X. Wu, National Institute of Standards and Technology M. Bal, National Institute of Standards and Technology J. Long, National Institute of Standards and Technology H.S. Ku, National Institute of Standards and Technology R. Lake, National Institute of Standards and Technology D.P. Pappas, National Institute of Standards and Technology |
| Correspondent: | Click to Email |
We developed a 50 Ohm transmission-line based superconducting kinetic inductance traveling-wave (KIT) amplifier using high inductance material NbTiN. The nonlinearity originates from the kinetic inductance of the superconductor and enables amplification. Often, the impedance of the transmission line is significantly higher than the 50 Ohm microwave environment due to the dominance of kinetic inductance over geometric inductance at micron size scales. To address this impedance mismatch, we engineered “fingers” on each side of the original coplanar waveguide KIT [1] to introduce extra capacitance that decreases the impedance to approximately 50 Ohm [2,3]. Those extra “fingers” also function to create a band stop at higher frequency to bend the dispersion relation between wave vector (k) and frequency (f), which allows us to apply the pump frequency within a wide span of a few GHz and achieve several GHz gain bandwidth for chosen pump frequency. Another advantage of this structure is that it significantly reduces the phase velocity, hence shortening the physical length of this device. Gain measurements based on both four wave mixing and three wave mixing will be presented.
[1] Appl. Phys. Lett. 108, 012601 (2016); https://doi.org/10.1063/1.4937922
[2] Journal of Applied Physics 119, 083901 (2016); https://doi.org/10.1063/1.4942362
[3] Appl. Phys. Lett. 110, 152601 (2017); https://doi.org/10.1063/1.4980102