The nonlinear coupled-mode equations are rewritten by even and odd modes.We study modulation instability(MI) of dispersion-shifted fiber couplers when either even or odd mode is launched alone by using zero-dispersion...The nonlinear coupled-mode equations are rewritten by even and odd modes.We study modulation instability(MI) of dispersion-shifted fiber couplers when either even or odd mode is launched alone by using zero-dispersion wavelength relatively long(quasi-cw) pulses.The result shows that there are new types of MI in both the normal-dispersion and the anomalous-dispersion regimes.MI is concerned with forth-order dispersion and has no relation with third-order dispersion.Quasi-cw can be changed into pulses array under certain conditions.We can extract super short pulse from this.Furthermore,the bandwidth of gain spectra widens and its strength accretes as the input power increases.展开更多
基金National Natural Science Foun-dation of China (No.60468001)
文摘The nonlinear coupled-mode equations are rewritten by even and odd modes.We study modulation instability(MI) of dispersion-shifted fiber couplers when either even or odd mode is launched alone by using zero-dispersion wavelength relatively long(quasi-cw) pulses.The result shows that there are new types of MI in both the normal-dispersion and the anomalous-dispersion regimes.MI is concerned with forth-order dispersion and has no relation with third-order dispersion.Quasi-cw can be changed into pulses array under certain conditions.We can extract super short pulse from this.Furthermore,the bandwidth of gain spectra widens and its strength accretes as the input power increases.
