A hydrocarbon monitoring cable including resistance to development of defects in a fiber optic core thereof. The core defect resistance may be in the form of resistance to defect causing agents of a downhole environment such as hydrogen. This may be obtained through the use of a carbon layer about the fiber optic core. However, in light of the differing coefficients of thermal expansion between such a carbon layer and an outer polymer jacket, an intermediate polymer layer of a third coefficient of thermal expansion may be disposed between the carbon and jacket layers. Thus, the intermediate polymer layer may be of a third coefficient of thermal expansion selected so as to avoid fiber optic defect causing thermal expansion from the downhole environment itself. Additionally, the monitoring cable may include an electrically conductive layer about the fiber optic core that is positively charged to repel other positively charged fiber optic defect causing agents of the downhole environment. Furthermore, a polymer-based absorbing layer for absorbing such defect causing agents may be disposed about the fiber optic core for protection.