Ma Jin-Dong, Wu Hao-Yu, Lu Qiao, Ma Ting, Shi Lei, Sun Qing, Mao Qing-He. Fiber-type difference frequency generation infrared optical frequency comb based on the femtosecond pulses generated by a mode-locked fiber laserJ. Acta Physica Sinica, 2018, 67(9): 094207. DOI: 10.7498/aps.67.20172503