Due to the limitation of the electrical OFDM signal and electrical Fast Fourier Transform (FFT), all-optical OFDMs have recently received much attention. Accordingly, this research study was conducted to investigate the effect of phase noise in the performance of an all-optical OFDM transmission system with 4-point FFT single mode fiber (SMF) links by considering the effects of fiber length, input laser power and a number of channels. In all optical systems, the transmitter side consists of a comb power generator, wavelength selected switch and an optical QAM generator. A comb power generator generates channels with a frequency separation of f=25 GHz. Subsequently, a Wavelength Selected Switch (WSS) was used to split subcarriers and then the subcarriers were modulated individually with Optical QAM modulators. As the results show, a higher number of channels led more phase noise in terms of XPM and FWM nonlinearities, and signal power was the main factor in nonlinear fiber optics. As a consequence, there is more phase noise distortion at a higher signal power for a higher number of channels rather than the lower number of channels.

This book consists of two parts. The first part is on the development of the proposition that if there exists a type of function, then there exists a functional with the same type based on the proposition of the inheritance and generalizability properties of a function in a functional. This study presents the abstract convex, increasing positively homogeneous and convex-along-rays functionals via this proposition. The second part concerns the investigation of the use of a global search optimization algorithm called the Cutting Angle Method (CAM) on Optimal Control Problems (OCP). Many algorithms are available for solving OCP, but they are basically local search algorithms. To overcome the problem associated with local searches, most OCP are modeled as Linear Quadratic Regulator (LQR) problems in the hope that the solution found estimates of the true global solution to the original problem. However, in doing so, a lot of information carried by the original problem might be lost in its translation into LQR models. CAM being a global search algorithm is expected to overcome this problem. It can be used alone or in combination with a local search to find the global solution. CAM has been successfully used on functions, however, OCP are functionals. To do this, a model has been introduced based on inheritance and generalizability properties to demonstrate that the optimization algorithms that are used for functions can also be extended for use in functionals. Based on these properties, the study discovered that with the Unit Vectors Combinations Technique (UVCT) proposed in this research, CAM could successfully work on functionals in general and OCP particularly. To help speed up the convergence of CAM, the literature proposed the use of local searches for the determination of the initial solution. In a case study done in the research, CAM was successfully combined with a local search known as the Dynamic Integrated System Optimization and Parameter Estimation (DISOPE) algorithm. Moreover, the initial solution given by the DISOPE algorithm has been verified as a global influence by CAM.

The purpose of this book was to investigate the temperature and input energy dependency of Nd:YAG laser performance pumped by flashlamp. A commercial laser rod Nd:YAG laser crystal was utilized as a gain medium. The laser rod was placed parallel to a linear flashlamp filled by xenon gas at 450 Torr. The Nd:YAG crystal together with the flashlamp was flooded with a coolant comprising of a mixture with 60% ethylene glycol and 40% distilled water, which covers a range of temperature from -30oC to +60oC. Spectroscopic properties of the Nd:YAG rod under pulsed flashlamp pumping was investigated from the output fluorescence spectrum of the flashlamp radiation and the Nd:YAG rod. The linewidth of each fluorescence line was measured for an estimation of an effective emission cross section and saturation intensity. The influence of temperature and input energy on a fluorescence emission cross section of Nd3+:YAG crystal was studied. The cross-section was found to decrease as the temperature and the input energy was increased. The inter-stark emission showed a Lorentzian line shape indicating homogeneous broadening. This was attributed to the thermal broadening mechanism of the emission line. The spectral widths and shifts of the emission lines for the three and four level inter-Stark transitions within the respective intermanifold transitions of 4F3/2 4I9/2 and 4F3/2 4I11/2 were investigated over the range of 0 to 75 J. The emission lines for the 4F3/2 4I9/2 transitions shifted towards a longer wavelength and broadened, while the positions and linewidths for the 4F3/2 4I11/2 transitions remained unchanged with the increase of input energy. Finally, the temperature dependence of quasi-three-level laser transitions for long pulse Nd:YAG laser was also investigated. The laser performances at both 938.5 nm and 946.0 nm were also found to be inversely proportional to temperature, and the slope efficiency was unchanged with temperature. The reduction was due to the mechanism of phonon scattering as well as a broadening effect while the temperature increased.