Mode-locked fibre lasers for ultrafast gyroscopic measurements

Abstract

Modern applications are constantly pushing the limits of current technologies, requiring further improvements in their precision. The advances in laser development significantly contribute to the achievements of modern technologies. One of the niches of precision technologies is gyroscopic measurements, where laser-based gyroscopes deliver unparalleled accuracy. Nonetheless, laser gyroscopes are subjected to the general limitation as ’lock-in’ effect, which restricts the lowest measurable angular velocity. The usage of pulsed laser sources, such as mode-locked lasers, can mitigate this deleterious effect and benefit the laser gyroscope development.The extensive studying of ultrafast lasers over the last few decades significantly improved their performance, extending their applications to extremely precise measurements such as optical clocks and telescope calibration. However, the usage of ultrafast lasers for the detection of angular rotations is still rudimentary and requires further studies.

In this manuscript, our goal is to contribute to the scientific achievements in the area of ultrashort pulses interferometry and, in particular, gyroscopic applications. We aim to deliver novel approaches for phase measurements at high data frequencies by using the recent advances in fast electronics and ultrafast measurement techniques. Firstly, we study bidirectional mode-locked fibre laser and its applicability for the detection of angular movements. Indicating the main obstacles to achieve continuous reliable results, in the following chapter we propose another interferometric setup, which provides the measurements of the pulse-to-pulse phase drift and can be used to characterise the phase noise of a pulse train or being exploited for interferometry. Finally, we demonstrate a passive gyro setup based on interferometric measurements, which inherits all the benefits of the usage of ultrashort pulses, while the phase noises of the laser source are significantly mitigated. We conclude that ultrashort pulses can benefit many phase-based applications, which require high resolution and high data rates, including but not limited to gyroscopic measurements.

Date of Award	Sept 2021
Original language	English
Supervisor	Sergei Turitsyn (Supervisor)