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Comparing optical-microwave conversion and all-microwave control schemes for a transmon qubit

Volodymyr Monarkha, Massimo Borrelli, Reza Hajitashakkori Kenari, Mohammad Kobba, Eugenio Cataldo, Beer de Zoeten, Mahnaz Zarrinfar, Kamal Pandey, Abhinand Pusuluri, Filippo D. Michelacci, Eliot Jouan, Bennett Sprague, Simon Groeblacher, Thierry C. van Thiel, Robert Stockill, Russell E. Lake

Abstract

We report a comparative study on transmon qubit control using (i) conventional attenuated coaxial microwave line and (ii) an optical control system using modulated laser light delivered over telecommunications optical fiber to a photodiode located at the 1K stage of a dilution cryostat. During each experiment, we performed repeated measurements of the energy relaxation and coherence times of a transmon qubit using one of the control signal delivery methods. Each measurement run spanned 20 hours of measurement time and from these datasets we observe no measurable effect on coherence of the qubit compared to random coherence fluctuations. Our results open up the possibility of large scale integration of the optical qubit control system.

Comparing optical-microwave conversion and all-microwave control schemes for a transmon qubit

Abstract

We report a comparative study on transmon qubit control using (i) conventional attenuated coaxial microwave line and (ii) an optical control system using modulated laser light delivered over telecommunications optical fiber to a photodiode located at the 1K stage of a dilution cryostat. During each experiment, we performed repeated measurements of the energy relaxation and coherence times of a transmon qubit using one of the control signal delivery methods. Each measurement run spanned 20 hours of measurement time and from these datasets we observe no measurable effect on coherence of the qubit compared to random coherence fluctuations. Our results open up the possibility of large scale integration of the optical qubit control system.
Paper Structure (8 sections, 1 equation, 3 figures, 2 tables)

This paper contains 8 sections, 1 equation, 3 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Experimental setup
  3. Measurement Results
  4. Discussion
  5. Source stability
  6. Photodiode temperature and dephasing
  7. Thermal budget and scaling
  8. Conclusion

Figures (3)

  • Figure 1: Schematic diagram showing the measurement layout. The drive and readout signals are either delivered to the photodiode (a) over a single mode optical fiber or injected to the sample trough a coaxial attenuated input line connected to a coupled port of a directional coupler. A photographic image of the photodiode assembly is shown on the inset (b)
  • Figure 2: Histograms of energy relaxation time T$_{1}$ and Ramsey T$^{*}_{2}$ accumulated over the same time period of 20 hours for control and readout input signals delivered over a microwave coaxial transmission line (a,b) or optical fiber (c,d), showing mean values, standard deviation and standard error in mean. Black line shows a fit of the normal distribution to the histogram. Time evolution of T$_{1}$,T$^{*}_{2}$ for a long interleaved measurement sequence with optical drive.
  • Figure 3: Ramsey measurement curve tilt (a) for the time series of $T^{*}_{2}$ measurement done with optical control or microwave control. Optical power setpoint deviation over time period of 12 hours (b).