Executive Summary : | In recent days silicon photonics has attracted considerable research interests because of its potential applications in the wavelength region extending from near- to mid-infrared. In this connection it may be pointed out that nonlinear pulse reshaping in silicon core fiber (SCF) or silicon on insulator (SOI) waveguide based devices has created tremendous attraction in the research community due to their useful operation in the domain of optical signal processing, high speed communication, wavelength conversion, supercontinuum generation and many more. The wide use of dispersion and nonlinearity engineered SCFs and waveguides with different structures plays a major role in this regard. The refractive index difference between silicon core and standard silica cladding is quite high which permits the tight confinement of light waves within smaller dimensions of both devices. Moreover, silicon exhibits a large third-order nonlinearity, with very high Kerr nonlinearity and much larger Raman gain coefficient than standard silica glass in the telecommunication band. Silicon exhibits typical features like two photon absorption (TPA), free-carrier absorption (FCA), free carrier dispersion (FCD) etc. However we must mention that the SCFs are fully compatible with standard fiber fabrication procedures such that the device yield can be enhanced with reduced costs. With the introduction of SOI technology as well it is possible to fabricate the device in a millimeter scale. Nowadays the self-similar parabolic pulses have opened new avenues in the field of fundamental and applied research in photonics. The other pulse shapes like triangular, rectangular etc. have also important applications as well. The so designed simple planar/buried/ridge shaped SOI waveguides are capable of such nonlinear pulse reshaping. The single mode SCFs both in passive or active domain can be effectively used to study different aspects of nonlinear pulse propagation whether used in anomalous or normal dispersion regime. The effect of different input pulse shapes like, Gaussian, Super Gaussian, Sech or other types can open new avenues in the domain of optical signal processing. In anomalous dispersion regime the SCF is able to split the single pulse into multiplet such that one can generate high repetition rate pulse train within a very short length when compared with standard silica based fiber. The effect of tapering will be studied in SCFs in terms of providing virtual gain to such fibers as tapering is unavoidable for fabrication. The suitably designed fibers or waveguide as proposed here may create supercontinuum in the mid IR region of operating wavelength. The combination of suitably designed waveguides can be used as well in the domain of adiabatic wavelength conversion, optical switching and other photonic applications. The output temporal and spectral shapes of the pulses will be investigated thoroughly for different conditions of fiber parameters and pulse parameters. |