Semiconductor Laser Dynamics

This is a collection of 18 papers, two of which are reviews and seven are invited feature papers, that together form the Photonics Special Issue “Semiconductor Laser Dynamics: Fundamentals and Applications”, published in 2020. This collection is edited by Daan Lenstra, an internationally recognized specialist in the field for 40 years

Study of wavelength switching time in tunable semiconductor micro-ring lasers: experiment and travelling wave description

We report in this paper the wavelength switching features of semiconductor ring lasers that are wavelength tunable based on filtered optical feedback. The filtered feedback provides a wavelength dependent loss mechanism in these devices with which a particular longitudinal mode, and thus a particular wavelength, can be selected by changing the filter characteristics of the feedback channel. We investigate how the wavelength switching speed depends on the amplitude of the modulation of the switching driving signal and on the different phase factors within the filtering branches of the SRL. We compare qualitatively the experimental results with numerical simulations based on a travelling wave model. We also investigate the dynamical behavior of the lasing and nonlasing longitudinal modes in the two channels of the clockwise and the counter-clockwise directions. We show the crucial importance of various phase relation factors on the wavelength switching behavior. Finally, we discuss what limits the switching speed and how we can accelerate it

Synchronization and prediction of chaotic dynamics on networks of optoelectronic oscillators

The subject of this thesis is the exploration of chaotic synchronization for novel applications including time-series prediction and sensing. We begin by characterizing the nonlinear dynamics of an optoelectronic time-delayed feedback loop. We show that synchronization of an accurate numerical model to experimental measurements provides a way to assimilate data and forecast the future of deterministic chaotic behavior. Next, we implement an adaptive control method that maintains isochronal synchrony for a network of coupled feedback loops when the interaction strengths are unknown and time-varying. Control signals are used as real-time estimates of the variations present within the coupling paths. We analyze the stability of synchronous solutions for arbitrary coupling topologies via a modified master stability function that incorporates the adaptation response dynamics. Finally, we show that the master stability function, which is derived from a set of linearized equations, can also be experimentally measured using a two-node network, and it can be applied to predict the convergence behavior of large networks

Traveling wave modeling of nonlinear dynamics in multisection semiconductor lasers

A hierarchy of 1 (time) + 1 (space) dimensional first-order partial differential equation (traveling wave) models is used for a description of dynamics in individual semiconductor lasers, various multisection semiconductor lasers, and coupled laser systems. Consequent modifications of the basic traveling wave model allow for taking into account different physical effects such as the gain dispersion, the thermal detuning, the spatial hole burning of carriers, the nonlinear gain saturation, or various carrier exchange processes in quantum dot lasers. For illustration, the model was applied for simulations of dynamics in complex ring laser with four branches of filtered feedback. Finally, several advanced techniques for model analysis such as calculation of instantaneous optical modes, finding of steady states, and numerical continuation and bifurcation analysis of the model equations were discussed and illustrated by example simulations

Advances in Optical Amplifiers

Optical amplifiers play a central role in all categories of fibre communications systems and networks. By compensating for the losses exerted by the transmission medium and the components through which the signals pass, they reduce the need for expensive and slow optical-electrical-optical conversion. The photonic gain media, which are normally based on glass- or semiconductor-based waveguides, can amplify many high speed wavelength division multiplexed channels simultaneously. Recent research has also concentrated on wavelength conversion, switching, demultiplexing in the time domain and other enhanced functions. Advances in Optical Amplifiers presents up to date results on amplifier performance, along with explanations of their relevance, from leading researchers in the field. Its chapters cover amplifiers based on rare earth doped fibres and waveguides, stimulated Raman scattering, nonlinear parametric processes and semiconductor media. Wavelength conversion and other enhanced signal processing functions are also considered in depth. This book is targeted at research, development and design engineers from teams in manufacturing industry, academia and telecommunications service operators

Diode-pumped IμM neodymium lasers and their internal frequency doubling

In this thesis the design, construction and performance of several diode-laser pumped continuous-wave neodymium lasers are described. These lasers were operated both around 1 mum and, by internal frequency-doubling, at 0.5 mum. The main emphasis has been on the assessment of the various laser designs with regard to their potential for efficient, high-power visible operation. A variety of pumping geometries, resonator configurations, gain media and internal frequency-doubling schemes were investigated, and their relative merits explored. Both side-pumping and end-pumping arrangements were employed, with Nd:YAG, Nd:YLF and Nd:YVO4 being used as gain media. Travelling-wave and standing-wave resonator designs were used. The polarisation-rotation effect in non- planar ring resonators was investigated and used to obtain single-frequency output. Single-frequency 0.5 mum powers up to 1.2 W were generated, and the highest 0.5 mum output power achieved was 4 W on two-longitudinal modes spaced by 450 MHz. The highest 1 mum output power achieved was 10 W, with a slope efficiency of 43%. Maximum pump powers for the lasers were in the region 15 - 35 W. A review of diode-laser pumped devices is included, with particular emphasis on the role of the spatial distributions of the pump and signal fields, because this is an important limiting factor in the performance of diode-pumped bulk laser systems. The criteria governing the harmonic output power when internally frequency-doubling are discussed. Issues relating to noise in the harmonic output, and techniques for its avoidance, are also discussed

Articles indexats publicats per investigadors del Campus de Terrassa: 2013

Aquest informe recull els 228 treballs publicats per 177 investigadors/es del Campus de Terrassa en revistes indexades al Journal Citation Report durant el 2013Preprin