Microstructured optical fibers, also known as photonic crystal fibers (PCFs) or holey fibers, have attracted growing interest during the last decade, owing to their wide range of optical properties accessible thanks to a freedom of designs that cannot be achieved with conventional fibers. Due to these characteristics, they found a large variety of applications ranging from optical communication to light sources or sensing. As an example, one can cite the broad and powerful supercontinuum sources used for fluorescence imaging, flow cytometry or characterization of optical components. Another interest of these PCFs lies in the possibility of using only pure silica glasses to design the fibers. This is particularly relevant when the aim is to achieve hardened devices operating in harsh environment like in space or in nuclear industries. This communication will show that the use of the sol-gel polymeric route can be applied to the preparation of high purity silica glass rods for the achievement of active PCF cores with conventional and unconventional compositions. As an example, results on the synthesis of Erbium- and Ytterbium-doped rods and their characterization will be presented. These rods have been used to fabricate PCFs with Er3+ and Yb3+-doped pure silica cores. Effects of this synthesis on the spectroscopic properties of the rare-earth ions will be discussed together with the performances of the doped PCFs employed as amplifiers or laser sources.