An integrated optical modulator operating at cryogenic temperatures

Felix Eltes*, Gerardo E Villarreal-Garcia, Daniele Caimi, Heinz Siegwart, Antonio Andreas Gentile, Andy S Hart, Pascal Stark, Graham D Marshall, Mark G Thompson, Jorge Barreto, Jean Fompeyrine, Stefan Abel*

*Corresponding author for this work

Research output: Contribution to journalLetter (Academic Journal)peer-review

106 Citations (Scopus)
851 Downloads (Pure)


Photonic integrated circuits (PICs) operating at cryogenic temperatures are fundamental building blocks required to achieve scalable quantum computing and cryogenic computing technologies1,2. Silicon PICs have matured for room-temperature applications, but their cryogenic performance is limited by the absence of efficient low-temperature electro-optic modulation. Here we demonstrate electro-optic switching and modulation from room temperature down to 4 K by using the Pockels effect in integrated barium titanate (BaTiO3) devices3. We investigate the temperature dependence of the nonlinear optical properties of BaTiO3, showing an effective Pockels coefficient of 200 pm V−1 at 4 K. The fabricated devices show an electro-optic bandwidth of 30 GHz, ultralow-power tuning that is 109 times more efficient than thermal tuning, and high-speed data modulation at 20 Gbps. Our results demonstrate a missing component for cryogenic PICs, removing major roadblocks for the realization of cryogenic-compatible systems in the field of quantum computing, supercomputing and sensing, and for interfacing those systems with instrumentation at room temperature.
Original languageEnglish
Pages (from-to)1164-1168
Number of pages6
JournalNature Materials
Early online date6 Jul 2020
Publication statusPublished - 1 Nov 2020

Structured keywords

  • Bristol Quantum Information Institute
  • QETLabs
  • Photonics and Quantum


  • Silicon photonics
  • Quantum optics
  • Nanophotonics and plasmonics
  • Ferroelectrics and multiferroics


Dive into the research topics of 'An integrated optical modulator operating at cryogenic temperatures'. Together they form a unique fingerprint.

Cite this