Fabrication tolerances for traveling wave parametric amplifiers

Resonantly phase matched traveling wave parametric amplifiers (TWPAs) [1] are sensitive to device fabrication errors. We develop a method to analyze the performance of the TWPA with emulated fabrication variations and different process parameters. We begin with an ideal analytic model and use circuit analysis and full-wave modeling to perturbatively calculate the full-circuit dispersion relation. We use this to find fabrication tolerances to different circuit parameters as well as ways to mitigate that sensitivity. We demonstrate that these robust designs with fabricated amplifiers achieve reasonable parametric gain and instantaneous bandwidth, suitable for multi-qubit multiplexed readout.

[1] K. O’Brien, et al., Phys. Rev. Lett. 113, 157001 (2014).