Quantum decoherence of dark pulses in optical microresonators

Chenghao Lao; Xing Jin; Lin Chang; Heming Wang; Zhe Lv; Weiqiang Xie; Haowen Shu; Xingjun Wang; John E Bowers; Qi-Fan Yang

doi:10.1038/s41467-023-37475-z

Quantum decoherence of dark pulses in optical microresonators

Nat Commun. 2023 Mar 31;14(1):1802. doi: 10.1038/s41467-023-37475-z.

Authors

Chenghao Lao^#¹, Xing Jin^#¹, Lin Chang^#², Heming Wang³, Zhe Lv¹, Weiqiang Xie^{3

4}, Haowen Shu², Xingjun Wang², John E Bowers⁵, Qi-Fan Yang^{6

7}

Affiliations

¹ State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China.
² State Key Laboratory of Advanced Optical Communications System and Networks, School of Electronics, Peking University, 100871, Beijing, China.
³ Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106, USA.
⁴ State Key Lab of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
⁵ Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106, USA. bowers@ece.ucsb.edu.
⁶ State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China. leonardoyoung@pku.edu.cn.
⁷ Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China. leonardoyoung@pku.edu.cn.

^# Contributed equally.

Abstract

Quantum fluctuations disrupt the cyclic motions of dissipative Kerr solitons (DKSs) in nonlinear optical microresonators and consequently cause timing jitter of the emitted pulse trains. This problem is translated to the performance of several applications that employ DKSs as compact frequency comb sources. Recently, device manufacturing and noise reduction technologies have advanced to unveil the quantum properties of DKSs. Here we investigate the quantum decoherence of DKSs existing in normal-dispersion microresonators known as dark pulses. By virtue of the very large material nonlinearity, we directly observe the quantum decoherence of dark pulses in an AlGaAs-on-insulator microresonator, and the underlying dynamical processes are resolved by injecting stochastic photons into the microresonators. Moreover, phase correlation measurements show that the uniformity of comb spacing of quantum-limited dark pulses is better than 1.2 × 10^-16 and 2.5 × 10^-13 when normalized to the optical carrier frequencies and repetition frequencies, respectively. Comparing DKSs generated in different material platforms explicitly confirms the advantages of dark pulses over bright solitons in terms of quantum-limited coherence. Our work establishes a critical performance assessment of DKSs, providing guidelines for coherence engineering of chip-scale optical frequency combs.