Wyniki wyszukiwania - BazTech

1

The effect of cladding geometry on the absorption efficiency of double-clad fiber lasers

Javadimanesh M., Ghavami S. S., Khorsandi A.

Optica Applicata

|

2016

|

Vol. 46, nr 2

277--289

EN

In the present work, the inner cladding geometries of a typical double-clad fiber laser are studied and numerically simulated for different cladding shapes to obtain the maximum absorption efficiency for the pump beam. This is performed by using the ray tracing approach and dislocating the fiber core from the center to impose the asymmetry on the investigated geometries. The high absorption efficiency of ~94.5% was obtained for the optimized offset D-shaped double-clad fiber. The hexagonal shape is proposed as a new geometry for the inner cladding to attain higher absorption efficiency. It was found that the absorption efficiency of ~68% for a symmetrical hexagonal can be improved to ~95% for an asymmetrized hexagonal-shaped double-clad fiber laser. Eventually the genetic algorithm was used to enhance the performance of the investigated geometries. This resulted in the further increasing of pump beam absorption efficiency of 99.5% in the genetic algorithm optimized asymmetrized hexagonal shape.

2

Establishment of motion model for wave capture buoy and research on hydrodynamic performance of floating-type wave energy converter

Gao H., Li B.

Polish Maritime Research

|

2015

|

S 1

106--111

EN

Floating-type wave energy converter has the advantages of high wave energy conversion efficiency, strong shock resistance ability in rough sea and stable output power. So it is regarded as a promising energy utilization facility. The research on hydrodynamic performance of wave capture buoys is the precondition and key to the wave energy device design and optimization. A simplified motion model of the buoys in the waves is established. Based on linear wave theory, the equations of motion of buoys are derived according to Newton’s second law. The factors of wave and buoys structural parameters on wave energy absorption efficiency are discussed in the China’s Bohai Sea with short wave period and small wave height. The results show that the main factor which affects the dynamic responses of wave capture buoys is the proximity of the natural frequency of buoys to the wave period. And the incoming wave power takes a backseat role to it at constant wave height. The buoys structural parameters such as length, radius and immersed depth, influence the wave energy absorption efficiency, which play significant factors in device design. The effectiveness of this model is validated by the sea tests with small-sized wave energy devices. The establishment methods of motion model and analysis results are expected to be helpful for designing and manufacturing of floating-type wave energy converter.

3

Analiza warunków wzbudzania światłowodów aktywnych typu dwupłaszczowego

Konieczny P., Zając A., Świderski J.

Biuletyn Wojskowej Akademii Technicznej

|

2005

|

Vol. 54, nr 4

5-21

PL

W artykule przedstawiono dwa modele numeryczne, pozwalające na analizę warunków wzbudzania dwupłaszczowych światłowodów aktywnych przeznaczonych do konstrukcji laserów włóknowych. Główna uwaga skupiona zastała na badaniach wpływu geometrii włókna aktywnego na wartość efektywnego współczynnika sprawności absorpcji, parametru który jest jednym z głównych wyznaczników całkowitej sprawności lasera włóknowego. Analiza ta prowadzona była w ujęciu optyki geometrycznej oraz optyki falowej. Powstałe programy komputerowe są doskonałym narzedziem, pomocnym przy doborze optymalnych parametrów włókna aktywnego.

EN

The paper presents the analysis of excitation conditions of active double-clad optical fibres designed for a fibre laser construction. The main focus was research concerning the active fibre geometry influence on the value of effective absorption efficiency coefficient - the parameter, which is one of the main determinants of the total fibre laser efficiency. The whole analysis was conducted in the geometrical and wave method approximation. The computer programs studied are a very helpful tool in selection of optimal parameters of active double-clad optical fibres.