Ultrafine electro-optical frequency comb based on cascade phase modulation with cyclic frequency shifting

作者:Wang, Changhe; Sun, Yuxin; Zhao, Qilai; Yang, Changsheng; Zeng, Chun; Feng, Zhouming; Zhang, Yu; Li, Li; Zhou, Kaijun; Wei, Xiaoming; Yang, Zhongmin; Xu, Shanhui
来源:Optics Letters, 2023, 48(17): 4665-4668.
DOI:10.1364/OL.498007

摘要

An ultrafine electro-optical frequency comb (EOFC) with plentiful comb teeth is demonstrated. Adopting a single-frequency fiber laser as a light source, cascade phase modulation based on a sinusoidal signal and a frequency-time transformation (FTT) signal is executed to generate the EOFC with high fineness. Meanwhile, a cyclic fast frequency shifting strategy is introduced to boost the number of comb teeth and the bandwidth of the EOFC. As a result, an EOFC with 12600 comb lines covering a broad bandwidth from -6.3 GHz to 6.3 GHz is established, corresponding to an ultrafine comb space of 1 MHz. Moreover, the power fluctua-tion of a comb tooth is less than 0.5 dBm. This state-of-the-art EOFC has significant potential in the field of precision spec-troscopy.

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