High Power Raman Fiber Amplifiers for large-scale Quantum Infrastructures

Bridging fundamental quantum experiments from the lab to real-world applications – like multi-1000-qubit quantum computers or large-scale quantum networks – requires enormous efforts to scale all building blocks by orders of magnitude. This includes the laser systems, which need to deliver powers in the range of 10 to 100 W at various wavelengths. In addition, the laser must emit in a narrow band and highly polarized manner and have exceptional stability.

We present a Raman fiber amplifier (RFA) which fulfills all above mentioned requirements in a single system. In combination with frequency conversion, we demonstrate a reliable route to generate wavelengths in the near infrared, visible, and UV, which are not directly accessible by common scientific high power lasers based on Ytterbium or Erbium doped fibers. The RFA can provide any center-wavelength between 1120 nm and 1400 nm with a tuning range of 10 nm. Powers up to 25 W are available of-the-shelf and up to 100 W have been demonstrated in prototypes. The RFA linewidth – given by the seed laser – is typically around 100 kHz. We demonstrate exceptional long-term power stability of < 0.5 % RMS deviation over 100 hours, as well as low short-term relative intensity noise (RIN) < 1 % between 10 Hz and 10 MHz.

First RFA systems are meanwhile installed in labs around the world and show excellent performance and stability in cutting edge quantum experiments. Examples will be presented.