A coating material characterized by wide-range thermal stability, water repellence, and physiological inertness, is newly employed as a dielectric layer in the dielectric-coated silver hollow optical fiber. This material, whose trade name is OC-300, is a semi-inorganic polymer based on the structural unit R2SiO, where R is an organic group. A smooth hardened film is formed at room-temperature on the silver layer by using a liquid-phase coating technique. The transmission properties of the OC-300 coated silver hollow fiber are evaluated for infrared laser light. Sterilization experiments by using an autoclave shows that the hollow fiber showed strong durability and promising application in medical filed as well as in other harsh environment.