High power scaling of optical amplifiers on the basis of the stimulated Raman scattering in optical fibers

There are several reasons for focusing the interest on the Raman Scatt ering phenomenon. First, the RS phenomenon is not bound to the special range of wavelengths. Secondly, properties of the gain curve (the shape and the magnitude) can be tailored by an employment of properly selected pump sources. Thirdly, the RS process has the unique feature of repeating itself. Thus, the achievable gain bandwidth of the amplifying medium can be considerably extended. The amount of frequency converted power depends on the intensity and length of the beam interaction. Fiber medium shows superior performance of the optical fiber in terms of nonlinear interacti on by the factor of six or seven orders of magnitude when compared with bulk. Moreover, the geometry of the optical fiber features excellent cooling properties. Thus, the opti mal cooling conditions are ensured. The aim of this thesis is to gain deeper understanding of the processes that govern, accompany or limit the Raman Scattering phenomena in optical fibers when pursuing the goal of maximum achievable output power. Having recognized the limitations, countermeasures are suggested as design recommendation.