A direction related polarizer (DRP) was used in a laser cavity to eliminate spatial hole burning of gain medium in a bidirectional Er-doped fiber ring laser. A stable operation of single longitudinal mode was achieved with comparable intensities for both clockwise and counterclockwise direction. A beat signal of 30 dB over noise was observed. This laser used as a gyroscope was demonstrated and a good linear relation between the beat frequency shift and the cavity rotation rate was acquired.