To compress the pulse width of a short laser pulse, a single mode optical fiber and grating pair were used. The output pulse of the CW mode-locked Nd:YLF laser was launched into a single mode fiber of 500m long to generate the self-phase modulated chirped pulse and then the chirped pulse was compressed again by holagraphic grating pair.
A theoretical analysis of the self-phase modulation inside a optical fiber and compression by using grating pair were studied in this research. The theoretical values of the spectral and pulse width broadening factors were calculated to be 1.38 and 1.23, respectively. Also, the theoretical value of a compressed pulse width at optimum condition was calculated to be 0.2ps. To measure the pulse widths of the frequency chirped and compressed pulses, the optical autocorrelator was designed and fabricated in this experiment. The optical auto-correlator was made of KDP crystal, rotating glass block, and prism reflectors. The KDP was used to generate the SHG by non-collinear phase matching to increase S/N. The spectral broadening factor and pulse width broadening factor were measured to be the 2.80 and 1.37(52ps), respectively, and the pulse width of the compressed pulse by grating pair was reduced by factor of 11(4.7ps), when the Nd:YLF laser output pulse was 38ps and 1.62KW. These measured values are comparable to the theoretical values.
