An Yb-fiber frequency comb phase-locked to microwave standard and optical reference<xref rid="cpb_29_3_030601fn1" ref-type="fn">*</xref><fn id="cpb_29_3_030601fn1"><label>*</label><p>Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDA1502040404 and XDB21010400) and the National Natural Science Foundation of China (Grant Nos. 91850209 and 11774234).</p></fn>

An Yb-fiber frequency comb phase-locked to microwave standard and optical reference**

Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDA1502040404 and XDB21010400) and the National Natural Science Foundation of China (Grant Nos. 91850209 and 11774234).

Wang Hui-Bo^{1, 2}, Han Hai-Nian^{2, 3, †}, Zhang Zi-Yue^{2, 3}, Shao Xiao-Dong^{2, 3}, Zhu Jiang-Feng¹, Wei Zhi-Yi^{1, 2, 3}

(a) Spectrum expansion for 972 nm after the photonic crystal fiber. (b) Detection of free-running f_beat signal in 100 kHz resolution bandwidth.