A series of ternary phosphate glass systems required for infrared (IR) photonic device fabrication is synthesized by the melt-quenching technique. The effect of replacing (divalent) ZnO with (monovalent) Na 2 O on optical properties of the glass systems is investigated. The dependence of the refractive index on composition is measured over a wavelength range of 1 to 2.5 μm; the second-order nonlinear refractive index is inferred. The different factors that play a role on controlling the glass refractive index, such as electronic polarizability, bridging and non-bridging oxygen, optical basicity, and ionic interaction parameter of oxides are discussed. IR vibrational spectroscopy is used as a structural probe of the nearest neighbor environment in the glass network. The present glasses are proper to be applied in C -band telecommunication systems around 1550 nm.
Lithium tungsten borate photonic glass is prepared by the conventional melt-quench technique. Due to semiconductor-like behavior of zinc oxide, the glass is doped by ZnO to adapt its optical nonlinearity. Fresnel-based spectrophotometric measurements and Lorentz dispersion theory are applied to study (in a very wide range of photon energy from 0.5 to 6.2 eV) the dispersion of second-order refractive index, two-photon absorption coefficient, and third-order optical susceptibility of the glass. The figure of merit (FOM) needed for optical switching applications is estimated. We reveal the importance of determining the dispersion of the optical nonlinear parameters to find out the appropriate operating wavelength for optimum FOM of the glass.
The induced variations of complex third-order susceptibilities in bent single-mode fiber at the standard operating wavelengths, 1300 and 1550 nm, is studied using Fizeau interferometry for radius of curvature ranges from 5 to 11 mm. At λ = 1300 nm and at the minimum radius of curvature R = 5 mm, the cladding real (dispersive) third-order susceptibility Re|χ(3)| = 1.167×10−15±0.8% electrostatic unit (esu) on the tensile side, whereas on the compressed side it is 1.309×10−15 esu. On the tensile side, the cladding imaginary (absorptive) third-order susceptibility Im|χ(3)| = 2.089×10−18±0.8% esu, whereas on the compressed side it is 2.118×10-18 esu. For λ = 1550 nm, the cladding Re|χ(3)| and Im|χ(3)| on the tensile side are 1.116×10-15 esu and 2.478×10-18 esu, whereas on the compressed cladding side they are 1.259×10-15 esu and 2.514×10-18 esu, respectively. At λ = 1300 nm and R = 5 mm, the core Re|χ(3)| is given by 1.318×10-15 esu on the tensile side and 1.324×10-15 esu on the compressed side. The asymmetry in Im|χ(3)| is given by 4.687×10-17 esu on the tensile side and by 4.89×10-17 esu on the compressed side. With λ = 1550 nm, the core Re|χ(3)| asymmetry is given by 1.267×10-15 esu on the tensile side and by 1.272×10-15 esu on the compressed side. For Im|χ(3)| its core asymmetry is provided by 5.561×10-17 esu on the tensile side and by 5.564×10-17 esu on the compressed side. The observed asymmetry in the measured complex third-order susceptibility components for bent fibers is attributed to the nonlinear response of Young's modulus of fiber material.
Multiple-beam Fizeau fringes are applied to study the effect of pure mechanical bending on some of single-mode optical fiber parameters. The induced birefringence and the associated radial refractive index profiles are measured as a function of fringe shift in case of very sharp radii of curvature. For the first time, the measured variation in index profiles incorporation with the minimum variance technique are employed to study some important parameters such as the oscillation energy, dispersion energy, and lattice energy profiles of the fiber cladding material predicting their radial variation with bending. The material dispersion profiles are specified as a function of the evaluated variations of the radial profiles of the oscillation and dispersion energies, respectively. The presented method provides an accurate study of the fiber parameters and their variations due to external effects, avoiding at the same time the complications of the dispersion measurements. Microinterferograms are given for demonstration.