Design of Fluorotellurite Microstructured Fibers With Near-Zero-Flattened Dispersion Profiles for Optical-Frequency Comb Generation

Abstract

We present the design of fluorotellurite microstructured fibers (FTMFs) with near-zero-flattened dispersion profiles in the wavelength range of 1500–1600 nm for optical frequency comb (OFC) generation. The FTMFs are based on TeO2-BaF2-Y2O3 glass with a zero-dispersion wavelength of ∼2160 nm. The fiber core is surrounded by the two layers of air holes. The addition of large size air holes in the outer layer is to shift the zero-dispersion wavelength of the fiber from ∼2160 nm to the wavelength region of 1500–1600 nm. The addition of small size air holes in the inner layer is to make the dispersion profile of the fiber become flat in the wavelength range of 1500–1600 nm. By optimizing the parameters (the core diameter, the air hole size, the pitch of air holes, etc.) of FTMFs, the fiber with the chromatic dispersion value between −0.5 and 0.3 ps/nm/km in the wavelength range of 1500–1600 nm is achieved. Furthermore, numerical simulations are used to show the potential of the fiber for OFC generation via cascaded four-wave mixing. Flat top OFC extending from 1500 to 1600 nm with tunable mode spacing from 25 to 100 GHz can be generated in a 2-m-long fiber by using a 1550-nm laser with a pulse width of 0.85 ps and a peak power of 49 W as the pump source. The effects of stimulated Brillouin scattering on OFC generation are also investigated.