Phase sensitive detection for mode-locked fiber laser gyroscope

We demonstrate a significant improvement in the performance of a mode-locked fiber laser gyroscope by using a lock-in amplifier. We show that the direct output of the lock-in amplifier has a desirable linear dependence on the rotation rate and is insensitive to the intensity difference between two pulses that causes phase error in the time interval measurement. Two orders of magnitude improvement is demonstrated in the long-term stability compared to that from previously reported time interval measurement.