News Article
GaSb lasers for low noise frequency conversion
Fraunhofer IAF's novel disk lasers will be the low-noise pump sources in German quantum network project
Fraunhofer IAF is developing GaSb-based semiconductor disk lasers in the wavelength range 2 to 2.2 µm in a new collaborative three year project called HIFI, funded by the German Federal Ministry of Education and Research (BMBF)
The aim of the project, 'Highly Integrated Quantum Frequency Converter of Highest Fidelity Based on Innovative Laser, fibre and Production Technology', is to develop Quantum frequency converters (QFCs). QFCs change the frequency or wavelength of photons in a targeted manner, to transmit them with low loss in fibre optic networks and to build quantum networks.
Fraunhofer IAF's semiconductor disk lasers (SDL) will be the low-noise pump sources for quantum frequency conversion. These are expected to meet the strict requirements of QFCs in terms of pump power, linewidth as well as stability, thus enabling high conversion efficiency with minimal wavelength noise that would interfere with the functionality of optical qubits.
Marcel Rattunde, project leader of HIFI on the part of Fraunhofer IAF, emphasises the importance of SDL development for the project: “In HIFI, a particularly low-noise type of frequency conversion is being developed. This necessitates a powerful, narrow-band laser in the range around 2.0 to 2.2 µm, which at the same time can be stabilised and spectrally tuned precisely to the application. GaSb based semiconductor disk lasers are the ideal light source for this purpose, because they can combine high output power with spectral tuneability, single-mode emission and long-term stability.”
Fraunhofer IAF researchers have developed a compact and spectrally single-mode GaSb SDL module that can be actively locked for absolute wavelength stability using a frequency comb at a wavelength of 2128 nm. It achieves a high output power currently exceeding 1.5 W, and is characterised by a narrow linewidth. With this module, the frequency of optical qubits from nitrogen-vacancy centers (NV centres) in diamond, which is 637 nm, can be converted to the telecom band.
Fraunhofer IAF will present this technology at Laser World of Photiics, which will take place in Munich from June 27 to 30, 2023.
