In this study, a Fiber Bragg Grating (FBG) based multiple temperature sensor array is designed using a conventional laser source that has 6 nm bandwidth in lowest signal level. This design is simulated in OptSim optical software. The simulation is conducted to observe 5 FBG's response to the temperature change individually. The temperature incident on the FBG's are gradually changed from 0 degrees C to 60 degrees C in 10 degrees C steps and the frequency shift is observed with RF spectrum analyzer and optical shift is observed with optical spectrum analyzer. As a result, 10 pm/degrees C wavelength shift observed in simulation.