High-performance lasers for fully integrated silicon nitride photonics
Silicon nitride (SiN) waveguides with ultra-low optical loss enable integrated photonic applications including low noise, narrow linewidth lasers, chip-scale nonlinear photonics, and microwave photonics. Lasers are key components to SiN photonic integrated circuits (PICs), but are difficult to fully integrate with low-index SiN waveguides due to their large mismatch with the high-index III-V gain materials. The recent demonstration of multilayer heterogeneous integration provides a practical solution and enabled the first-generation of lasers fully integrated with SiN waveguides. However, a laser with high device yield and high output power at telecommunication wavelengths, where photonics applications are clustered, is still missing, hindered by large mode transition loss, non-optimized cavity design, and a complicated fabrication process. Here, we report high-performance lasers on SiN with tens of milliwatts output power through the SiN waveguide and sub-kHz fundamental linewidth, addressing all the aforementioned issues. We also show Hertz-level fundamental linewidth lasers are achievable with the developed integration techniques. These lasers, together with high-Q SiN resonators, mark a milestone towards a fully integrated low-noise silicon nitride photonics platform. This laser should find potential applications in LIDAR, microwave photonics and coherent optical communications.
Additional Information© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received 05 April 2021; Accepted 19 October 2021; Published 17 November 2021. We acknowledge support from the Defense Advanced Research Projects Agency (DARPA) STTR project (W911NF-19-C-0003). Author Contributions: C.X. and P.A.M. designed the laser device. W.J. and M.P. provided the high-Q SiN resonator. C.X. and J.P. fabricated the laser device, with assistance from W.J. and W.X. J.G., C.X. and L.W. characterized the lasers and performed injection locking measurements, with assistance from B.S., H.W., Q.Y., and P.A.M. C.X analyzed the data. L.C. and D.K. packaged the laser. C.X. wrote the manuscript. All authors reviewed the manuscript. J.E.B, P.A.M, and K.J.V supervised the project. Competing interests: J.E.B is a cofounder of Quintessent and Nexus Photonics, whose focus is in related fields. Peer review information: Nature Communications thanks Haiwen Cai, Ashutosh Rao and the anonymous reviewer(s) for their contribution to the peer review of this work.
Published - s41467-021-26804-9.pdf
Submitted - 2104.08414.pdf
Supplemental Material - 41467_2021_26804_MOESM1_ESM.pdf
Supplemental Material - 41467_2021_26804_MOESM2_ESM.docx