Dan Savastru

By I. Lăncrănjan, R. Savastru, D. Savastru and S. Micloş

Part of the book: Numerical Simulation

By Sorin Miclos, Dan Savastru, Roxana Savastru and Ion Lancranjan

The aim of this chapter is to highlight the role of simulation methods as tools for analysis of low and medium average power fiber laser operated in passively Q-switched and/or mode-locking regimes into the design of various applications such as materials micro-processing of sensor applications. The chapter’s purpose consists in making available to specialists in the field of lasers, electro-optics and even nano-photonics improved procedures for designing high-accuracy remote sensors dedicated to large range of laboratory, industrial and military applications. The reason that this chapter deals with passive optical Q-switching and mode-locking techniques tailored for fiber lasers is the high percentage of sensing devices operating in this regime. Numerical simulation results obtained for this class of laser emitters can be used for other types of lasers, such as optical fiber lasers. There are briefly presented the two main mathematical methods used to analyze solid laser oscillators in passive optical Q-switching regime: the coupled rate equations approach and the iterative approach. The validation of the presented numerical simulation methods is done by comparison with experimental results.

Part of the book: Fiber Laser

By Dan Savastru, Sorin Miclos, Marina Tautan and Ion Lancranjan

The paper presents the results obtained in simulation of fiber Bragg grating (FBG) and long-period grating (LPG) sensors and their applications. The optical properties of FBG and LPG are firstly analyzed and, consequently, the basics of simulation models are provided. Coupled-mode theory and the transfer matrix methods are the two techniques used for the simulation of FBG and LPG. The numerical simulations are performed for an improved design of these types of fiber sensors, designs dedicated to specified applications. The different FBG types, i.e. the normal, chirped, apodized, according to different laws and tilted cases, are analyzed. Also, various LPG configurations are numerically simulated. The two main categories of sensing applications, for temperature and for mechanical stress/strain evaluation, are simulated for each type of fiber grating sensor. The chapter is intended to be a synthesis of already obtained results to which some results of research in development are added.

Part of the book: Modeling and Simulation in Engineering Sciences

By Valeriu Savu, Mădălin Ion Rusu and Dan Savastru

Following the interaction of a neutrino with saline environment, the Cherenkov cone will be generated. The electromagnetic effect of the Cherenkov cone is perpendicular to the cone generator and it has the energy directly proportional to the neutrino energy. In the saline environment, neutrinos with very high energies (noise – 115 dBm) can be determined. Investigation of these neutrinos will lead to the construction of a Cherenkov detector. The construction of a Cherenkov detector involves the design and the construction of a very large number of detection elements and of cascade amplifiers. Another necessary condition is to know exactly the distribution of the dielectric parameters of the saline environment. In order to know the distribution of the dielectric parameters of the saline environment, it is necessary to make a map of their distribution. Under these conditions, the number of detection elements will be optimized and also the optimal position of the future Cherenkov detector will be determined. In this chapter, we will present the methodology of calculating the detection elements and a method to determine the dielectric parameters. Measurements of attenuation of the propagation of electromagnetic waves in this environment will be presented. We will detail how to optimize a Cherenkov detector.

Part of the book: Nuclear Power Plants