Superconducting micro-resonator arrays with ideal frequency spacing
Xiangliang Liu, Weijie Guo, Y Wang, M Dai, L F. Wei , Bradley J. Dober, Christopher M. McKenney, Gene C. Hilton, Johannes Hubmayr, Jason E. Austermann, Joel N. Ullom, Jiansong Gao, Michael R. Vissers
We present a wafer trimming technique for producing superconducting micro-resonator arrays with highly uniform frequency spacing. With the light-emitting diode mapper technique demonstrated previously, we first map the measured resonance frequencies to the physical resonators. Then, we fine-tune each resonator's frequency by lithographically trimming a small length, calculated from the deviation of the measured frequency from its design value, from the interdigitated capacitor. We demonstrate this technique on a 127-resonator array made from titanium-nitride and show that the uniformity of frequency spacing is greatly improved. The array yield in terms of frequency collisions improves from 84% to 97%, while the quality factors and noise properties are unaffected. The wafer trimming technique provides an easy-to-implement tool to improve the yield and multiplexing density of large resonator arrays, which is important for various applications in photon detection and quantum computing.