Silicon photonics-based high-energy passively Q-switched laser

Neetesh Singh*, Jan Lorenzen, Milan Sinobad, Kai Wang, Andreas C. Liapis, Henry C. Frankis, Stefanie Haugg, Henry Francis, Jose Carreira, Michael Geiselmann, Mahmoud A. Gaafar, Tobias Herr, Jonathan D.B. Bradley, Zhipei Sun, Sonia M. Garcia-Blanco, Franz X. Kärtner

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
26 Downloads (Pure)


Chip-scale, high-energy optical pulse generation is becoming increasingly important as integrated optics expands into space and medical applications where miniaturization is needed. Q-switching of the laser cavity was historically the first technique to generate high-energy pulses, and typically such systems are in the realm of large bench-top solid-state lasers and fibre lasers, especially in the long wavelength range >1.8 µm, thanks to their large energy storage capacity. However, in integrated photonics, the very property of tight mode confinement that enables a small form factor becomes an impediment to high-energy applications owing to small optical mode cross-sections. Here we demonstrate a high-energy silicon photonics-based passively Q-switched laser with a compact footprint using a rare-earth gain-based large-mode-area waveguide. We demonstrate high on-chip output pulse energies of >150 nJ and 250 ns pulse duration in a single transverse fundamental mode in the retina-safe spectral region (1.9 µm), with a slope efficiency of ~40% in a footprint of ~9 mm2. The high-energy pulse generation demonstrated in this work is comparable to or in many cases exceeds that of Q-switched fibre lasers. This bodes well for field applications in medicine and space.

Original languageEnglish
Pages (from-to)485-491
Number of pages7
JournalNature Photonics
Issue number5
Early online date2024
Publication statusPublished - May 2024
MoE publication typeA1 Journal article-refereed


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