Sub-milliwatt, widely-tunable coherent microcomb generation with feedback-free operation
Abstract
Microcombs are revolutionizing optoelectronics by providing parallelized, mutually coherent wavelength channels for time-frequency metrology and information processing. To implement this essential function in integrated photonic systems, it is desirable to drive microcombs directly with an on-chip laser in a simple and flexible way. However, two major difficulties are preventing this goal: 1) generating mode-locked comb states usually requires a significant amount of pump power and 2) the requirement to align laser and resonator frequency significantly complicates operation and limits the tunability of the comb lines. Here, we address these problems by using microresonators on an AlGaAs on-insulator platform to generate dark-pulse microcombs. This highly nonlinear platform dramatically relaxes fabrication requirements and leads to a record-low pump power of less than 1 mW for coherent comb generation. Dark-pulse microcombs facilitated by thermally-controlled avoided mode-crossings are accessed by direct DFB laser pumping. Without any feedback or control circuitries, the comb shows good coherence and stability. This approach also leads to an unprecedented wide chirping range of all the comb lines. Our work provides a route to realize power-efficient, simple and reconfigurable microcombs that can be seamlessly integrated with a wide range of photonic systems.
Cite
@article{arxiv.2112.08904,
title = {Sub-milliwatt, widely-tunable coherent microcomb generation with feedback-free operation},
author = {Haowen Shu and Lin Chang and Chenghao Lao and Bitao Shen and Weiqiang Xie and Xuguang Zhang and Ming Jin and Yuansheng Tao and Ruixuan Chen and Zihan Tao and Shaohua Yu and Qi-Fan Yang and Xingjun Wang and John E. Bowers},
journal= {arXiv preprint arXiv:2112.08904},
year = {2021}
}