The primary data encoding technology used in fiber-optic cables is non-return-to-zero (NRZ) encoding, and increasingly, more advanced forms of NRZ like NRZ-Inverted (NRZI) and modulation techniques like Pulse-Amplitude Modulation (PAM), particularly PAM4, are employed for higher. The primary data encoding technology used in fiber-optic cables is non-return-to-zero (NRZ) encoding, and increasingly, more advanced forms of NRZ like NRZ-Inverted (NRZI) and modulation techniques like Pulse-Amplitude Modulation (PAM), particularly PAM4, are employed for higher. Fiber-optic communication is a form of optical communication for transmitting information from one place to another by sending pulses of infrared or visible light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is preferred. Fiber-optic cables have revolutionized modern communication systems by enabling high-speed, long-distance data transmission through pulses of light. Unlike old-fashioned copper cables, fiber optics leverage sophisticated encoding methodologies to maximize bandwidth, reach, and reliability. Unlike traditional copper wires that use electrical signals to transmit data, fiber-optic systems rely on light pulses to carry information at unprecedented. Single Mode – The core diameter is almost equal to the wave length of the emitted light so that it propagates along a single path.