Chalogenide glasses, with favorable properties like high linear and nonlinear refractive index, good transmittance in the infrared region, low phonon energy and photosensitivity make these glasses a potential candidate in lasers, amplifiers and high brightness sources for remote sensing applications. The present work deals with the linear and nonlinear optical properties of ternary (SeTe-Bi) and quaternary (Se-Te-Bi-Sn) chalcogenide thin films. In this thesis we have studied following chalcogenide glass systems.I. Se85-xTe15Bix (0 x 5)II.Se84-xTe15Bi1.0Snx (0 x 8)The bulk samples were...