The Authors report a novel structure of a simple Q switched Er doped fiber laser in which a fiber grating Michelson interferometer is used as a laser cavity mirror. It offers a precise wavelength selecting as well as a feedback reflectivity modulating functions. A stable Q switched fiber laser emitting light at 1545.70 nm with a peak power of 500 mW, repetition rate of 17 kHz and pulse width of 1.3 μs, was successfully demonstrated.