Laser gyroscopes afford extremely precise measurement of ultraslow angular velocity and play an irrefutable role in engineering seismology, tidal detection, aviation, aerospace, satellite navigation, and other inertial systems. With recent progress of mode-locked fiber lasers, particularly the realization of effective bidirectional generation, their applications in the fields of gyroscopic sensing have attracted tremendous attention. Besides the merits of excellent structure compactness, maintenance-free operation, and rather low cost, remarkably, the mode-locked laser gyroscope presents a promising approach for eliminating the lock-in effect caused by the synchronization of counterpropagating resonant frequencies, which is the most severe sensing limitation of traditional laser gyroscopes. In this paper, recent advancements and perspectives in this research are reviewed. The fundamentals of gyroscopic sensing employing mode-locked pulse lasers are presented. Architectures of novel mode-locked laser gyroscopes inspired by ultrafast optics, including bright-soliton mode-locked laser gyroscopes and dark-soliton mode-locked laser gyroscopes, are described in detail. Bottlenecks and deficiencies of the exhibited mode-locked laser gyroscopes owning to inherent physical mechanisms or measurement methods currently used are further analyzed. Finally, feasible methods of improving the performance of mode-locked laser gyroscopes are broadly expounded upon to build a bridge between their scientific development research and practical applications. 

Advancement and expectations on mode-locked laser gyroscopes

This paper comprehensively investigated noise characteristics of superluminal propagation based on low-noise single-frequency Brillouin lasing oscillation with the aid of a population inversion dynamic grating. Thanks to high-degree polarization alignment between the Brillouin pump and the lased Stokes lightwaves in polarization maintaining fibers, efficient Brillouin lasing resonance with over 10-dB relative intensity noise suppression has been demonstrated to activate Brillouin loss-induced anomalous dispersion in the vicinity of pump signals, benefiting a noise-insensitive superluminal propagation along kilometer-long optical fibers with robust resistance to ambient disturbance. Consequently, sinusoidally modulated pump signals experienced the time advancement of 4634.0 ns at the group velocity of 10.63 c . Results show that the variance of the fractional advancement with polarization maintaining fibers is 2.54 × 10−4 which is two orders of magnitude lower than that of conventional single mode fibers. Furthermore, the dependence of the group velocity on the modulation frequency was experimentally investigated, showing good agreement with the theoretical analysis.

Stabilized Long-Distance Superluminal Propagation Based on Polarization-Matched Low-Noise Brillouin Lasing Resonance

We experimentally demonstrated the longest fast light and superluminal propagation along kilometer optical fibers by utilizing a polarization maintaining fiber-based Brillouin lasing oscillator incorporating a population inversion dynamic grating. © 2020 The Author(s)

Kilometer-long fast light and superluminal propagation via polarization-matched Brillouin lasing resonance in optical fibers

We demonstrated a high-efficiency random fiber laser based on hybrid gain mechanism of Brillouin and Erbium-doped fiber amplification as well as distributed random feedback from a weak FBG array.

High-efficiency Brillouin-Erbium Random Fiber Laser via Distributed Random Feedback from a Weak FBG Array

We experimentally achieved stabilized Brillouin-induced fast light and superluminal propagation in kilometer-long optical fibers by introducing linearly polarized single-longitudinalmode Stokes lasing resonance.

Stabilized Fast Light and Superluminal Propagation via Linearly Polarized Brillouin Lasing Oscillation

We experimentally demonstrated Brillouin-induced fast light based on random lasing oscillation with random feedback of distributed Rayleigh scattering in optical fibers.

Jilin Zhang

Papers

Stabilized Long-Distance Superluminal Propagation Based on Polarization-Matched Low-Noise Brillouin Lasing Resonance

Kilometer-long fast light and superluminal propagation via polarization-matched Brillouin lasing resonance in optical fibers

High-efficiency Brillouin-Erbium Random Fiber Laser via Distributed Random Feedback from a Weak FBG Array

Stabilized Fast Light and Superluminal Propagation via Linearly Polarized Brillouin Lasing Oscillation

Long-distance Fast Light Propagation Based on Brillouin Random Lasing Oscillation in Optical Fibers