Fiber optics is not unfamiliar to everyone, we are most exposed to fiber-optic Internet access, fiber is widely used for its absolute advantages. However, many friends will always confuse the fiber and cable. In fact, they are very different. The following Fiber Closure manufacturer will introduce you to the fiber? The full name of the fiber is an optical fiber, which is a light-conducting tool that uses the principle of total reflection of light in fibers made of glass or plastic. The tiny fiber is encapsulated in a plastic sheath so that it can bend without breaking. Generally, the transmitting device at one end of the optical fiber transmits a light pulse to the optical fiber using a light emitting diode or a laser beam, and the receiving device at the other end of the optical fiber detects the pulse using the photosensitive member. Since the conduction loss of light in an optical fiber is much lower than the loss of electrical conduction in a wire, an optical fiber is often used as long-distance information transmission. Fiber structure: The bare fiber is generally divided into three layers, the center high-refractive-index glass core, the middle of which is a low-refractive-index silica glass cladding, and the outermost is a resin coating for reinforcement. Numerical aperture: The light incident on the end face of the fiber cannot be transmitted entirely by the fiber, but only the incident light within a certain angle range. This angle is called the numerical aperture of the fiber. The larger numerical aperture of the fiber is advantageous for the docking of the fiber. Optical fibers produced by different manufacturers have different numerical apertures.