Photonic chip-based low-noise microwave oscillator

Creators: Kudelin, Igor; Groman, William; Ji, Qing-Xin; Guo, Joel; Kelleher, Megan L.; Lee, Dahyeon; Nakamura, Takuma; McLemore, Charles A.; Shirmohammadi, Pedram; Hanifi, Samin; Cheng, Haotian; Jin, Naijun; Wu, Lue; Halladay, Samuel; Luo, Yizhi; Dai, Zhaowei; Jin, Warren; Bai, Junwu; Liu, Yifan; Zhang, Wei; Xiang, Chao; Chang, Lin; Iltchenko, Vladimir; Miller, Owen; Matsko, Andrey; Bowers, Steven M.; Rakich, Peter T.; Campbell, Joe C.; Bowers, John E.; Vahala, Kerry J.¹; Quinlan, Franklyn; Diddams, Scott A.

1. California Institute of Technology

Abstract

Numerous modern technologies are reliant on the low-phase noise and exquisite timing stability of microwave signals. Substantial progress has been made in the field of microwave photonics, whereby low-noise microwave signals are generated by the down-conversion of ultrastable optical references using a frequency comb^1,2,3. Such systems, however, are constructed with bulk or fibre optics and are difficult to further reduce in size and power consumption. In this work we address this challenge by leveraging advances in integrated photonics to demonstrate low-noise microwave generation via two-point optical frequency division^4,5. Narrow-linewidth self-injection-locked integrated lasers^6,7 are stabilized to a miniature Fabry–Pérot cavity⁸, and the frequency gap between the lasers is divided with an efficient dark soliton frequency comb⁹. The stabilized output of the microcomb is photodetected to produce a microwave signal at 20 GHz with phase noise of −96 dBc Hz⁻¹ at 100 Hz offset frequency that decreases to −135 dBc Hz⁻¹ at 10 kHz offset—values that are unprecedented for an integrated photonic system. All photonic components can be heterogeneously integrated on a single chip, providing a significant advance for the application of photonics to high-precision navigation, communication and timing systems.

Copyright and License

© The Author(s) 2024. 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 licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence 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 licence, visit http://creativecommons.org/licenses/by/4.0/.

Acknowledgement

We thank B. Long for the illustration in Fig. 5 and K. Chang and N. Hoghooghi for comments on the manuscript. Commercial equipment and trade names are identified for scientific clarity only and do not represent an endorsement by NIST. The research reported here performed by W.Z., V.I. and A.M. was carried out at the Jet Propulsion Laboratory at the California Institute of Technology under a contract with the National Aeronautics and Space Administration. This research was supported by the DARPA GRYPHON Program (grant HR0011-22-2-0009), the National Aeronautics and Space Administration (grant 80NM0018D0004) and NIST.

Contributions

P.T.R., J.E.B., K.J.V., A.M., F.Q. and S.A.D. conceived the experiment and supervised the project. I.K., W.G. and S.A.D. wrote the paper with input from all authors. I.K. and W.G. together with Q.-X.J. and J.G. built the experiment and performed the optical frequency division experiment. L.W. prepared the distributed feedback laser butterfly packages for the experiment. Q.-X.J., J.G., W.J., L.W., C.X. and L.C. prepared the microcomb and spiral resonators for the experiment. M.L.K. and F.Q. built the Fabry–Pérot cavity. D.L., T.N., C.A.M., Y. Liu and F.Q. provided the optically derived microwave reference and aided in the microwave phase noise measurement system. P.S., S. Hanifi and S.M.B. provided the regenerative divide-by-two circuit. H.C., N.J., S. Halladay, Z.D., Y. Luo, O.M., F.Q. and P.T.R. contributed to the cavity integration scheme. W.Z., V.I. and A.M., contributed to phase noise limitation analysis and system integration. J.B. and J.C.C. provided modified unitravelling carrier detectors. All authors contributed to the system design and discussion of the results.

Data Availability

All data for the figures in this manuscript are available at https://doi.org/10.6084/m9.figshare.24243511.

Conflict of Interest

The authors declare no competing interests.

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