This thesis mainly studying the impact of TiO2 and K2O these two compounds in the Chromium-doped glasses and glass-ceramics. Due to the method of Modified Chemical Vapor Deposition (MCVD) of Chromium-doped fiber preform production process, the Ti and K elements have some difficulties; thus, we discuss the influences of these two elements. We hope to improve the composition after knowing these two elements, in order to make the Chromium-doped fiber preform well. We change the weight percent of TiO2 and K2O in the glass composition, in order to observe the influences. Then, we measure their optical and material properties. The results of experiments show that the well-known nucleation agent: TiO2, have no effect of the crystalline phase. However, its function is to help the formation of crystals. We can conclude by the results of X-ray Diffraction (XRD). K2O plays an important role of the Mg2SiO4 phase. To add K2O or not, is the most important reason to affect the Mg2SiO4 phase formation. We will discuss in detail in this thesis about the phase difference for the fluorescence characteristics of Chromium-doped glass and glass-ceramics. What¡¦s more, we use the previously developed two times laser heat-treatment, hoping to successfully apply for Chromium-doped fiber drawing in the future. The laser heat-treatment of CO2-laser can induce the crystal in the glasses. However, this method only needs just a few seconds, which can reduce the cost of heat-treatment. In addition, we can reduce the crystalline size by using the method of two times laser heat-treatment, which can decrease the scattering loss. Also, we will discuss the impact of laser heat-treatment after changing the composition.