Design and Performance of a Velocity-Matched Broadband

Optical Modulator with Superconducting Electrodes

[Japanese Version]

[Abstract ]

The performance of a LiNbO3 optical modulator employing superconducting electrodes as a transmission line for a traveling-wave signal has been studied theoretically as well as experimentally. In the case of velocity matching between signal and optical waves using a shielding plane on top of a coplanar waveguide, numerical calculations of the attenuation constants of both superconducting and normal-conducting transmission lines indicate that the performance of the optical modulator can be far superior to that using normal-metals with respects to the figure of merit of bandwidth/driving-voltage. Microwave operation of a velocity-matched traveling-wave-type optical modulator with superconductor electrodes (NbN) has been successfully demonstrated. In the freqency range between dc and 26.5[GHz] it is shown that the obtained modulation depth is in good agreement with the theoretically expected one.

[contents]

  1. Introduction
  2. Theoretical Performance
  3. Experiment
  4. Conclusion
  5. Reference

back