Numerical analysis of induced phase modulation between two ultrashort pulses in silica fiber by the extended finite-difference time-domain method

摘要

We have analyzed the induced phase modulation (IPM) for ultrashort (74 fs) two-pulse propagation in a silica fiber by the extended finite-difference time-domain (FDTD) method, considering all exact Sellmeier-fitting values and nonlinear polarization P-NL involving the Raman response function. We show that nonlinear polarization causes several phenomena in spectral characteristics of propagated pulses, such as self-phase modulation (SPM), self-steepening, Raman response and IPM, by the extended FDTD method. To the best of our knowledge, this is the first IPM calculation by the extended FDTD method for the simultaneous propagation of, two ultrashort (74 fs) laser pulses in a silica fiber.