Numerical modelling and optimization of actively Q-switched waveguide lasers based on liquid crystal transducers.

We have recently experimentally demonstrated that a novel liquid crystal-based photonic transducer for sensing systems could be utilized as an active Q-switch in a miniaturised and integrated waveguide laser system. In this paper, we now present a comprehensive numerical modelling study of this novel laser architecture by deriving a set of equations that accurately describe the temporal optical response of the liquid crystal cell as a function of applied voltage and by combining this theoretical model with laser-rate equations. We validate the accuracy of this model by comparing the results with previously obtained data and find them in excellent agreement.

Compact integrated actively Q-switched waveguide laser.

A miniaturized deformed helix ferroelectric liquid crystal transducer cell was used in combination with a femtosecond laser inscribed active waveguide to realize a compact actively Q-switched laser source. The liquid crystal cell was controlled by a low-voltage frequency generator and laser pulse durations below 40 ns were demonstrated at repetition rates ranging from 0.1 kHz to 20 kHz and a maximum slope efficiency of up to 22%.