Fig. 1. Schematic diagram of the proposed LDV based on a dual-polarization fiber grating laser. ISO: isolator; WDM: wdivision multiplexer; PD: photodetector; MFS: microwave frequency synthesizer; DAQ: data acquisition; DSP: digital signal processing.

Fig. 2. Received waveform for the rotation rate measurement of the grinding wheel. The rotation rate of the wheel is 960 rpm.

Fig. 3. Velocity versus the measured Doppler frequency shift. A fitted line for the measured results is also plotted as the solid line.

Fig. 4. (a) Received waveform after mixer, (b) its enlargement, (c) the recovered Doppler frequency shift, and (d) the moving average over 100 samples of (c).

Fig. 5. Velocity resolutions of the proposed LDV and the ratio between the resolution and the velocity.