“…Recently, a-C:H films for hermetic optical fiber coatings prepared by rf-PECVD using methane (CH 4 ) and hydrogen (H 2 ) as the precursor gases were studied [7,10]. When the carbon films were prepared by the rf-PECVD method, the characteristics of the films were affected by many factors such as the mixture ratio of reactive gases, self-bias voltage, substrate temperature, and so on [10,14,[16][17][18]. However, we have found no evidence of preview work to study the effect of substrate temperature on the properties of carbon-coated optical fibers prepared by rf-PECVD method.…”