Introduction

Finite-difference time-domain calculation with all parameters of Sellmeier's fitting equation for 12-fs laser pulse propagation in a silica fiber

“…For the single-cycle pulse generation experiment, we must use at least sub-5 fs [3], [7] or commercially available 12-fs pulses. Such a time regime is comparable to the Raman characteristic time of 5 fs [4] in a silica fiber. Therefore, it is very important to consider not only the accurate linear dispersion of silica but also the Raman effect in a silica fiber in the few-optical-cycles regime.…”

“…In this work, we have extended the FDTD method with nonlinear polarization involving the Raman response function (GJTH-algorithm) to 12-fs ultrabroad-band pulse propagation in a silica fiber with consideration of linear polarization including all exact Sellmeier-fitting values of silica with three resonant frequencies, in order to compare the calculation results with our experimental results [1], [2]. We also compare the extended FDTD method with the split-step Fourier (SSF) method which is the solution of the generalized nonlinear Schrödinger equation (GNLSE) with SVEA [4]. To the best of our knowledge, this is the first comparison be-1041-1135/02$17.00 © 2002 IEEE…”

“…For these experiments on generating few-optical-cycle pulses, characterizing the spectral phase of ultrabroad-band pulses analytically as well as experimentally is highly significant. Conventionally, the slowly varying envelope approximation (SVEA) has been used to describe the propagation of an optical pulse in a fiber [4]. However, if the pulse duration approaches the optical cycle regime ( 10 fs), this approximation becomes invalid.…”

“…However, if the pulse duration approaches the optical cycle regime ( 10 fs), this approximation becomes invalid. It is necessary to use the finite-difference time-domain (FDTD) method [5], [6] without SVEA [4]. Previous reports [5] by Goorjian, Joseph, Taflove, and Hagness (GJTH) proposed an excellent FDTD algorithm considering combination of the linear dispersion with one resonant frequency and the nonlinear terms with Raman response function.…”

“…As we can obtain both new and , the new electric field is obtained by substituting and into Newton's iteration algorithm [5], with a new value of obtained from(1-b).In our calculation, the parameters for a fused silica fiber in (3) are set as , , , m, m, and m [4], where and is the velocity of light in vacuum. We used the value of the nonlinear refractive coefficient m /W from [10], and the third-order susceptibility was found to be m /V at 800 nm, given by , where is the center angular frequency of the optical pulse.…”