Thesis (Ph.D.) - Cork Institute of Technology, 2016

Includes bibliographical references.

"Many modern technologies rely on laser devices, in areas such as communications, sensing and imaging. Examination and research into the fundamental operational dynamics of lasers and characterisation of laser performances, are a crucial tool in ensuring the quality and effectiveness of laser-based applications. The development of characterisation tools is an important part of improving upon existing technologies and advancing the next generation of devices. In this work, a real-time multiheterodyne detection technique is developed which allows for the study of dynamically varying pulse trains formed by optical frequency combs. Single-shot complex spectrum analysis is performed with a 50 MHz frame-rate on a series of dynamic amplitude and frequency modulated pulse trains. This high time-resolution characterisation method is the first known multiheterodyne technique to be applied to non-periodic waveforms. A real-time electric field reconstruction technique is also presented, for the characterisation of fast frequency-swept lasers. Phase measurement of the laser field output is achieved for a variety of lasers designed for optical coherence tomography applications. Swept sources with bandwidth of up to ~20 THz, and repetition rates of 200 kHz, are studied. The novel 3x3 fibre coupler-based interferometric method is shown to completely recover the complex electric field, enabling analysis of the spectral, temporal, coherence and dynamic properties of these lasers. Compared to pre-existing time-averaging methods, new experimental results demonstrate the ability to completely characterise the laser sweep and imaging properties in a single-shot, showing both inter- and intra-sweep properties. Finally, an optical random number generator scheme is presented, based on the operation of a turbulent fibre laser. Random bit streams of 1 Tb/s are demonstrated. These results are competitive with many state-of-the-art optical systems utilising more complex generation schemes. Furthermore, it is shown that in the absence of an external optical signal, the inherent electrical noise of a modern high-speed analogue-to-digital converter can be leveraged to provide Tb/s generation rates in a highly simple and cost-effective manner". - (Author's abstract)