A novel fiber-optic temperature sensing system is developed based on wavelength modulation,which utilizes the temperature dependence of the band edge absorption of infrared light in GaAs semiconductor.A semiconductor GaAs chip was used as sensitive component and a new reflective sensing probe was used in this system.The advantages of the probe are small size,perfect insulation and quick response.In addition,the diffraction technique based on CCD was used to demodulate reflected signal of the sen...