Analysis of ultrafast nonlinear phenomena’s influences on output optical pulses and four-wave mixing characteristics in semiconductor optical amplifiers

Abstract

We have analysed the output pulse characteristics of semiconductor optical amplifier (SOA). It is shown that they can be modified due to the variation of input parameters, such as, gain, input pulsewidth, input pulse energy and effects imposed by the medium. Therefore, the influence of these parameters are analysed on the output pulse shape, spectrum, chirp and pulsewidth. We have used the nonlinear propagation equation taking into account the gain spectrum dynamics, gain saturation which depends on carrier depletion, carrier heating, spectral hole-burning, group velocity dispersion, self-phase modulation and two photon absorption. We have used the finite-difference beam propagation method to simulate the wave evolution both in time and spectral domain in the SOA. We have also simulated the four-wave mixing characteristics between pulses for various input pulses. An accurate output pulse shape can be achieved by controlling the mentioned parameters. To the authors knowledge, pulse shaping in co-propagation regime due to medium effect and input pulse shapes in presence of all nonlinear effects relevant to picosecond regime have been studied comprehensively, for the first time in this work.

Comparison of pulse propagation and gain saturation characteristics among different input pulse shapes in semiconductor optical amplifiers

“…(3) [9][10][11][12][13][14] is used for the simulation of pulse propagation with different input pulse shapes in SOAs. The MNLSE uses the complex envelope V z , τ ( ) function of an optical pulse which is given in Eq.…”

“…We assumed the same values of A 1, A 2, B 1 and B 2 as for an AlGaAs/GaAs bulk SOA [9][10][11][12][13][14]. Generally, the fast Fourier transformation BPM (FFT-BPM) is used for analysis of the optical pulse propagation in optical fibres by successive iterations of the Fourier transformation and the inverse Fourier transformation.…”

“…Therefore, it is not possible to separate (3) into the linear propagation term and phase compensation term, and it is difficult to calculate (3) using the FFT-BPM. For this reason, we have used the FD-BPM [9][10][11][12][13][14] to solve this MNLSE.…”

“…This analysis is based on the MNLSE considering the non-linearities in SOA, such as self-phase modulation (SPM), two-photon absorption (TPA), group velocity dispersion (GVD), carrier depletion (CD), carrier heating (CH), spectral-hole burning (SHB), gain spectrum dynamics, and gain saturation in the SOA [5,7]. To solve the MNLSE, the finite-difference beam propagation method (FD-BPM) is used because of its short convergence time and excellent accuracy of the simulated results [8][9][10][11][12][13][14][15][16]. For simulation of pulse propagation with small propagation steps, FD-BPM is considered as the best method compared to others [8][9][10][11][12][13][14].…”

“…To solve the MNLSE, the finite-difference beam propagation method (FD-BPM) is used because of its short convergence time and excellent accuracy of the simulated results [8][9][10][11][12][13][14][15][16]. For simulation of pulse propagation with small propagation steps, FD-BPM is considered as the best method compared to others [8][9][10][11][12][13][14]. In this paper, we have numerically investigated and compared the output waveforms or Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/optcom propagated pulses characteristics and the gain saturation characteristics for different types of input pulse shapes in SOAs.…”