In the field of 5G and communication, the technical threshold of thin film filter (TFF) required for high-density division multiplexed passive optical fiber network (DWDM) systems is high. Coating technology and coating materials have become the key to the success of this field. In order to obtain a uniform thickness and stable coating rate on the surface of the coated object, the purity and density of the sputtering target become a key concern. Taiwan Applied Crystal possesses ceramic sintering technology, which can produce high-density (>95%) tantalum pentoxide and niobium pentoxide targets. There is no spark during the sputtering (or evaporation) process, and the coating rate is stable.