Improved Performance of Hermetic Optical Fiber for Harsh Environment

摘要

Optical fiber with significantly improved hermeticity is presented. In order to simulate a harsh environment, a hydrogen test chamber has been built capable of temperatures up to 200°C and hydrogen pressures up to 2000psi. Hydrogen induced loss at 1.24um was monitored in-situ and used to extract the characteristic time constants for hydrogen permeation through protective carbon coating. Data thus obtained is used to predict the lifetime of fiber at a given temperature and pressure. Carbon-coated fiber of this study exhibits more than one order of magnitude improvement of hermeticity compared with previously published data in the literature. The high performance hermetic fiber also manifests itself in its large stress corrosion parameter n-value (>240) and sustaining high pressure and high temperature water test under tightly bending conditions.