The unique merits of fiber Bragg grating

such as it is immune to electromagnetic field and easy to constitute a distributed sensors network

are effectively used for equipment health monitoring and testing mechanical characteristics of materials under high frequency stress load.The frequency of wavelength encoded signal demodulation is one of the key problems that limit the use of fiber Bragg grating sensor in high frequency signal environment.Mach-Zehnder interference technology is adopted to design a high-frequency demodulation system for fiber Bragg grating

which bases on phase generated carrier demodulation（PGCD）.With this designed demodulation system

the signals produced by sinusoidal stimulating and impact setup are measured.The experimental results are satisfied.The measurement of 10 kHz frequency is achieved.