Original research articleFew-cycle pulse generation from compression of supercontinuum by optimizing initial chirp in ANDi-PCF

We proposed and demonstrated a few-cycle pulse generation from compression of supercontinuum (SC) pulse by using a simple grating pair compressor. An all-normal dispersion photonic crystal fiber (ANDi-PCF) with nearly zero flattened dispersion at 1550 nm was chosen to generate a highly coherent SC. In such a fiber a highly coherent broadband SC with 20-dB wavelength from 1107 nm to 2551 nm is generated. It is found that the mechanism of spectral broadening is mainly dominated by self-phase modulation which results in the highly coherent SC generation. By using a grating pair compressor, an approximately 1.6-cycle pulse (8.4 fs) but only with compression quality of 56.55% can be obtained from compression of the highly coherent SC optical pulse. By optimizing the initial chirp of the pump pulse, we have successfully compressed the SC pulse to less than 10 fs with compression quality as high as 95.4%.