All-chalcogenide core-shell fibers for nonlinear applications
The extreme spectral broadening phenomenon called as Supercontinuum generation is considered as one of the most striking phenomenon in nonlinear optics. Due to their broad spectra and uniformly distributed power over the spectra supercontinuum sources have found wide range of applications in areas such as spectroscopy, frequency metrology, optical coherence tomography, microscopy and telecommunications. In this thesis, we propose a new method to fabricate multicore fibers made of chalcogenide glasses for the use of high power Supercontinuum generation. We designed and fabricated a new seven-core-structured fiber with chalcogenide core /chalcogenide cladding step-index fiber embedded in polymer matrix. After three successful iterative steps we fabricated seven-core chalcogenide glasses fiber which has diameter around 1.35 μm which is engineered to be approximately zero dispersion. The refractive indices of these two materials at 1550 nm are 2.73 and 2.61; as a result the NA is engineered to 0.8 at this wavelength. The step index structure of the fiber provides the very well-confinement of light to the core of the fibers. This enables the more interaction of light with the highly nonlinear part of the fiber and preserves light to be absorbed by the polymer jacket which has high absorbance at IR region. By using split step Fourier method we showed the potential of our fiber to generate supercontinuum covering from 1 μm to 3.5 μm.