The core: made of silica, molten quartz, or plastic, in which optical waves propagate. 5µm for multimode fiber and 9µm for single-mode. Total Internal Reflection ( an a er the fiber and ally internally reflected fiber' cone and better light collecti model - tFiber optic cables use light to transmit data, instead of electricity as in twisted pair cables. The core is the. The invention discloses a skeleton fiber bundle optical cable with semicircular skeleton grooves, and relates to an optical cable applied to a communication network. A central reinforcement part is. Fiber-optic communication is a method of transmitting data from one point to another by sending infrared light pulses through an optical fibre.