Development of oxide ceramic reinforcing fibers with improved thermomechanical properties via seeding and various sintering additives is yielding promising results fit to be used in future technology. Oxide ceramic CMCs offer a range of positive improvements to their alternatives such as but not limited to low density, high chemical and mechanical stability for high temperature applications. Nevertheless, research and development of a product with desired parameters still pose a challenge both technically and economically. The poster presents the latest progress of Fraunhofer Centre HTL in the area of oxide ceramic fibers for high temperature applications. The concentation lies in optimization of production of zirconia reinforced fibers. The topic delves deeper into the effects of grain size and chemical composition on creep resistance of the fiber material and the measurements using an advanced analytical thermo-optical technique.