Currently the world is experiencing a fast evolution of modern communication and information technologies and infrastructure development. Consequently, there is a growing need to be able to quickly and resource-efficiently receive, transmit and process information, monitor different physical processes, environment. For this purpose, optical communication systems and optical fiber sensors are directly suitable. This paper consists of a study of fiber Bragg grating (FBG) optical sensors, with particular emphasis on fiber optical temperature sensors. The experimental part is made of computer simulation by RSoft OptSim software, during which the temperature effects on five FBG optical sensors central wavelengths is investigated. This developed optical sensors network is combined with an optical transmission system on one shared 20 km long optical fiber. The line is divided into five parts with 4 km distance between each sensor. This is typical distance used in Latvia between cable manholes or cabinets where are placed fiber optical closures. Here the coexistence of multiple sensor network and 50 GHz spaced 4 channel non-return-to-zero (NRZ) intensity modulated wavelength division multiplexed (WDM) optical communication system with 10 Gbit/s downstream transmission is investigated and evaluated.