What is 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 a long-distance information transmission.
Fiber structure: The bare fiber is generally divided into three layers, the center high-refractive-index glass core, the middle 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.
What is the way to access the fiber?
Fiber-optic Internet access also belongs to a broadband connection method. Different from the way of connecting through a telephone line, ordinary ADSL Internet access is connected to the room through a telephone line and needs to be bundled with a telephone. The fiber-optic Internet access is directed by the optical fiber line. Entering the room, the connection interface of the general broadband line to the client is the RJ45 interface. Internet speed is faster than ADSL Internet access.
Advantages of fiber optic networks:
- fast. Telecom fiber access can provide high-speed bandwidth of 10Mbps, 100Mbps, 1000Mbps, realize bidirectional data synchronous transmission, and fast Internet access.
- the distance is far. The fiber connection distance is up to 70 kilometers, the capacity is large, and the fiber working frequency is 8-9 orders of magnitude higher than the current working frequency of the cable, and the developed capacity is large.
- Strong anti-interference ability. Because the optical fiber is a non-metallic dielectric material, it is not subject to strong electrical interference, electrical signal interference, and lightning interference, and has strong anti-electromagnetic pulse capability, which is conducive to confidentiality.
- The fiber broadband network is fast and stable.
- Convenient capacity expansion. A standard fiber-optic line with a bandwidth of 2M can easily be upgraded to 4M, 10M, 20M, up to 100M, and no equipment needs to be replaced.
- low loss. In a system consisting of coaxial cables, the loss of optical fibers is much smaller and does not change with temperature. There is no need to worry about fluctuations in the mains level due to changes in ambient temperature.
- lightweight. Because the fiber is very thin, plus waterproof layer, ribs, sheath, etc., the diameter of the cable consisting of 4 to 48 fibers is less than 13mm, which is much smaller than the diameter of the standard coaxial cable of 47mm. The fiber is fiberglass. The small specific gravity makes it small in diameter and light in weight and is easy to install.
- high fidelity. Intel said the fiber-optic transmission interface will replace USB.
- low cost. At present, some new Moore’s Laws, also called the laws of optics, have been proposed. The law states that the bandwidth of information transmitted over fiber is doubled every six months and the price is doubled. Due to the abundant materials for making optical fibers, the cost will be further reduced in the future, and the copper materials required for the cables are limited and the price will be higher and higher. Optical fiber transmission has an absolute advantage.
The difference between optical fiber and optical cable
Most of the optical fibers must be covered by several layers of the protective structure before use. The covered cables are called optical cables. The coated optical fibers can avoid damage to the surrounding environment, such as water, fire, electric shock, and the like. The components of the cable are fiber, the buffer layer, and cladding. The fiber and coaxial cable are similar, except that there is no mesh shielding layer. The center is the glass core of light transmission.