• Bipolar photodiode module operated at 4 K 

      Bardalen, Eivind; Nissilä, Jaani; Fordell, Thomas; Karlsen, Bjørnar; Kieler, Oliver; Øhlckers, Per (Chapter, 2020)
      An optoelectronic module for generating high frequency bipolar current pulses at 4 K was developed. Bipolar signals are generated by connecting a pair of photodiodes in series to coplanar waveguides on silicon. The ...
    • Characterization of high-precision resistive voltage divider and buffer amplifier for ac voltage metrology 

      Karlsen, Bjørnar; Lind, Kåre; Malmbekk, Helge; Øhlckers, Per (Peer reviewed; Journal article, 2019)
      A high-precision voltage buffer and a 10:1 resistive voltage divider have been constructed for use in ac voltage and electrical power metrology. Long-term stability of the buffer's dc response has been demonstrated by two ...
    • Driving a low critical current Josephson junction array with a mode-locked laser 

      Nissilä, J.; Fordell, Thomas; Kohopää, K.; Mykkänen, E.; Immonen, P.; Jabdaraghi, R. N.; Bardalen, Eivind; Kieler, Oliver; Karlsen, Bjørnar; Øhlckers, Per; Behr, Ralf; Manninen, A. J.; Govenius, J.; Kemppinen, A. (Peer reviewed; Journal article, 2021)
      We report proof-of-concept experiments on an optically driven Josephson voltage standard based on a mode-locked laser (MLL), a time-division multiplexer, and a cryogenic ultrafast photodiode driving an overdamped Josephson ...
    • High-Speed Pulsation of a Cryogenically Operable Bipolar Photodiode Module for the Josephson Arbitrary Waveform Synthesizer 

      Karlsen, Bjørnar; Bardalen, Eivind; Nissilä, Jaani; Fordell, Thomas; Kieler, Oliver; Palafox, Luis; Behr, Ralf; Malmbekk, Helge; Akram, Muhammad Nadeem; Øhlckers, Per (Peer reviewed; Journal article, 2020)
      This paper describes the development and testing of a prototype of a cryogenically operable bipolar photodiode module. Optical pulsation systems based on both a Mach-Zehnder modulator and a mode-locked laser have been used ...
    • Optically operated pulse-driven Josephson junction arrays and range extension using voltage dividers and buffer amplifiers 

      Karlsen, Bjørnar (Doctoral dissertations at the University of South-Eastern Norway;52, Doctoral thesis, 2019)
      Voltage dividers and buffer amplifier combinations can be used to transfer and extend traceability in voltage and electrical power metrology between a wide range of instruments. For voltages up to 1000 V, resistive voltage ...