• DOI:10.1063/5.0040882
• Corpus ID: 229331953

Mid-infrared quantum cascade laser frequency combs with a microstrip-like line waveguide geometry

@article{Kapsalidis2020MidinfraredQC,
  title={Mid-infrared quantum cascade laser frequency combs with a microstrip-like line waveguide geometry},
  author={Filippos Kapsalidis and Barbara Schneider and Matthew Singleton and Mathieu Bertrand and Emilio Gini and Mattias Beck and J{\'e}r{\^o}me Faist},
  journal={Applied Physics Letters},
  year={2020},
  volume={118},
  pages={071101}
}

• F. Kapsalidis, B. Schneider, +4 authors J. Faist
• Published 18 December 2020
• Physics
• Applied Physics Letters

In this work, a design for a mid-infrared quantum cascade laser frequency comb source that enhances the high frequency response and the comb characteristics of the device is presented. A state-of-the-art active region, grown on a heavily n-doped InP:Si substrate, was processed into a buried heterostructure with a microstrip-like line waveguide. As a result, the repetition rate frequency frep, around 11.09 GHz, can be locked to an injected narrow-linewidth radio frequency (RF) signal, over a range of more than 200 kHz with an injected power of −10 dBm, which outperforms normal buried heterostructure schemes by an order of magnitude. Moreover, under RF injection at powers higher than 20 dBm, the lasing spectrum is flattened and significantly broadened, from 24 cm − 1 to 65 cm − 1 in bandwidth, while at the same time, the coherence of the comb is maintained and verified.