A fiber lasers vibration sensor with high resulution is propoced and realized.The fiber laser sensor is made by writing Bragg grating into a section of high gain active fiber.Vibration signal applied on the fiber laser induces laser frequency shifts

and a polarization-insensitive unbalanced Michelson fiber interferometer is employed to transform the frequency shifts into phase shifts of the interferometer.After converting the output of the interferometer to electric signals

the signals are sampled and inputted into the computer

an phase generated carrier（PGC） demodulation technique is used to achieve high resolution interrogation.The experiment result demonstrates that the minimal detectable acceleration of this system is 200ngn/Hz at 250Hz

the result demonstrates the linear relationship between the acceleration and the wavelength shifts of FLS.