Ultrafast gyroscopic measurements in passive Mach-Zehnder interferometer via time-stretch technique

Gyroscopes play an important role in inertial navigation systems in ships, air- and space-craft [1] and astronomy [2] . However, the presence of the lock-in effect significantly hampers the further increase of their performance. Besides, modern self-navigation applications demand compactness with kHz data rates. Previous studies have demonstrated a potential of recently emerged time-stretch techniques, such as the Dispersive Fourier Transformation (DFT) [3] , [4] , for detection of the optical Sagnac effect through single-shot spectral measurements of ultrashort pulses [5] . In this work, we present a phase-based method to detect rotation in a passive all-fibre Mach-Zehnder interferometer (MZI) via assessing real-time dynamics of ultrashort pulses. Moreover, the lock-in effect is com-pletely eliminated since two pulses (reference and signal) are propagating in two different arms of the MZI. The resolution of the phase retrieval is 7.2 mrad that corresponds to an angular shift of 5.78 µ rad. The data rate is 15 MHz as determined by the repetition rate of the mode-locked laser used.