The number of optical cores in an optical fiber is the total number of equipment interfaces multiplied by 2, plus 10% to 20% of the spare quantity, and if the communication mode of the equipment has serial communication and equipment multiplexing, you can reduce the. The number of optical cores in an optical fiber is the total number of equipment interfaces multiplied by 2, plus 10% to 20% of the spare quantity, and if the communication mode of the equipment has serial communication and equipment multiplexing, you can reduce the. Fiber cores are the heart of fiber optic cables, transmitting light signals that carry data. Made from either high-quality glass or plastic, the core plays a critical role in determining the cable's performance. The number of. In this guide, we'll help you determine the right number of fiber cores for your specific application. First of all, clearly know the number of wiring points in this layer, calculate the number of switches, and whether the connections. • Fiber optic cables commonly come in multiples of 2 fiber increments, such as 6, 12, 24, 48, 72 and 144 fiber configurations. • Design engineers reserve spare fibers for potential breaks and future upgrades to the system.