**Measurement of Ultrashort Optical Pulses**

Yuqiang Deng1,\*, Qing Sun1, Shiying Cao2, Jing Yu1, Ching-yue Wang3 and Zhigang Zhang4 *1Optics Division, National Institute of Metrology, Beijing, 2Time and Frequency Center, National Institute of Metrology, Beijing, 3School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, 4School of Electronics Engineering and Computer Science, Peking University, Beijing, P. R. China* 
