Ge-As-Se chalcogenide thin films show a wide range of photosensitivity,which is utilized for the fabrication of micro-optical elements for integrated optics.The photosensitivity of Ge_xAs_(40)Se_(60-x)(x=0,15)chalcogenide thin films for UV light was presented.For that purpose,the bulk samples of Ge_xAs_(40)Se_(60-x)(x=0,15)chalcogenide glasses were prepared using conventional melt quenching technique,and thin films were prepared using thermal evaporation technique.These thin films were exposed to UV light for two hours.Amorphous natures of bulk samples and thin films were verified by XRD and chemical compositions were verified by EDX measurements.The thicknesses of the thin films were measured using a thickness profilometer.Linear optical analysis of these thin films was done using transmission spectra in wavelength range of 300-900 nm.Optical bandgap was determined by first peak of transmission derivative as well as extrapolation of Tauc's plot.R~2 analysis was done using R software to ensure that the material is indirect bandgap material.It is observed that two hours UV exposure causes photo-darkening along with photo-expansion in As_(40)Se_(60)thin films,while photo-bleaching and photo-densification for Ge_(15)As_(40)Se_(45)thin films.However,the amounts of photo-induced optical changes for Ge_(15)As_(40)Se_(45)thin films are smaller than those for As_(40)Se_(60)thin films.The changes in optical absorption,bandgap and thickness are understood based on the bonding rearrangement caused by UV exposure. Ge-As-Se chalcogenide thin films show a wide range of photosensitivity, which is utilized for the fabrication of micro-optical elements for integrated optics. The photosensitivity of Ge_xAs_ (40) Se_ (60-x) (x = 0,15) chalcogenide thin films for UV light was presented. For that purpose, the bulk samples of Ge_xAs_ (40) Se_ (60-x) (x = 0,15) chalcogenide glasses were prepared using conventional melt quenching technique, and thin films were prepared using thermal evaporation technique.These thin films were exposed to UV light for two hours. Amorphous natures of bulk samples and thin films were verified by XRD and chemical compositions were verified by EDX measurements. thicknesses of the thin films were measured using a thickness profilometer. Linear optical analysis of these thin films was done using transmission spectra in wavelength range of 300-900 nm. Optical bandgap was determined by first peak of transmission derivative as well as extrapolation of Tauc's plot. R ~ 2 analysis was done using R software t o ensure that the material is indirect bandgap material. It is observed that two hours UV exposure causes photo-darkening along with photo-expansion in As_ (40) Se_ (60) thin films, while photo-bleaching and photo-densification for Ge_ ( (40) As_ (40) Se_ (45) thin films are smaller than those for As_ (40) Se_ (60) As_ (40) Se_ (45) thin films.However, the amounts of photo-induced optical changes for Ge_ ) thin films. The changes in optical absorption, bandgap and thickness are based on the bonding rearrangement caused by UV exposure.