Increased multiplexing of superconducting microresonator arrays by post-characterization adaptation of the on-chip capacitors

Abstract

We present an interdigitated capacitor trimming technique for fine-tuning the resonance frequency of superconducting microresonators and increasing the multiplexing factor. We first measure the optical response of the array with a beam mapping system to link all resonances to their physical resonators. Then a new set of resonance frequencies with uniform spacing and higher multiplexing factor is designed. We use simulations to deduce the lengths that we should trim from the capacitor fingers in order to shift the resonances to the desired frequencies. The sample is then modified using contact lithography and re-measured using the same setup. We demonstrate this technique on a 112-pixel aluminum lumped-element kinetic-inductance detector array. Before trimming, the resonance frequency deviation of this array is investigated. The variation of the inductor width plays the main role for the deviation. After trimming, the mean fractional frequency error for identified resonators is -6.4e-4, with a standard deviation of 1.8e-4. The final optical yield is increased from 70.5% to 96.7% with no observable crosstalk beyond -15 dB during mapping. This technique could be applied to other photon-sensitive superconducting microresonator arrays for increasing the yield and multiplexing factor.

arXiv comment5 pages, 4 figures, accepted by APL

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Cited by in corpus (7)

• SLAC Microresonator RF (SMuRF) Electronics: A tone-tracking readout system for superconducting microwave resonator arrays
• Development of MKIDs for measurement of the Cosmic Microwave Background with the South Pole Telescope
• Understanding and minimizing resonance frequency deviations on a 4-inch kilo-pixel kinetic inductance detector array
• Investigation of reflection-based measurements of microwave kinetic inductance detectors in the optical bands
• NEW-MUSIC: The Next-generation Extended-Wavelength Multiband Sub/millimeter Inductance Camera
• AMKID -- a large KID-based camera at the APEX telescope
• Design of SPT-SLIM focal plane; a spectroscopic imaging array for the South Pole Telescope