Fiber optics transmit signals in the form of light pulses, using glass or organic glass as network transmission media. It consists of a fiber core, a cladding, and a protective sleeve. Fiber can be divided into single-mode fiber and multi-mode fiber. Single mode fiber only provides one optical path, which is complex to process, but has greater communication capacity and longer transmission distance. Multimode optical fibers use multiple optical paths to transmit the same signal, and control the transmission speed through the refraction of light.
Fiber optic cables are generally used for transmission in communication networks, and different types of fibers are selected according to the environment and transmission requirements during the transmission process. There are several types of optical fibers used in computer networks, including
A 8.3pm core/125pm shell, single-mode optical cable;
B 62.5um core/125um shell, multimode optical cable;
C 5OPm core/125mm casing, multimode optical cable;
D loopm core/140pm casing, multimode optical cable. Fiber optic cables are mainly composed of optical fibers (glass fibers as thin as hair), plastic protective sleeves, and plastic sheaths. There are no metals such as gold, silver, copper, or aluminum inside the cable, and it generally has no recycling value. Fiber optic cable is a type of communication line that consists of a certain number of optical fibers arranged in a certain way to form a cable core, which is wrapped with a sheath or even an outer protective layer to achieve optical signal transmission. Namely: a cable formed by a certain process of optical fiber (optical transmission carrier). The basic structure of optical cables is generally composed of several parts such as cable cores, reinforced steel wires, fillers, and sheaths. In addition, components such as waterproof layers, buffer layers, and insulated metal wires can be added as needed.
The main reasons for the rapid development of fiber optic cables are the following characteristics:
1. The transmission bandwidth is very wide and the communication capacity is large;
2, Low transmission loss, long relay distance, especially suitable for long-distance transmission;
3, Strong resistance to lightning and electromagnetic interference;
4, Good confidentiality, not easily eavesdropped or intercepted data;
5, Small size and light weight;
6, Low bit error rate and high transmission reliability;
7, The price is continuously decreasing.
The basic structure of optical cables is generally composed of several parts such as cable cores, reinforced steel wires, fillers, and sheaths. In addition, components such as waterproof layers, buffer layers, and insulated metal wires can be added as needed. The optical cable consists of three parts: reinforced core and cable core, sheath and outer protective layer. There are two types of cable core structures: single core type and multi-core type. Single core type has two types: solid core type and bundle core type; There are two types of multi-core types: strip type and unit type. There are two types of outer protective layers: metal armor and non armor.
The manufacturing process of optical cables generally includes the following steps:
1. Fiber selection: Select fibers with excellent transmission characteristics and qualified tension.
2. Dyeing of optical fibers: Standard full spectrum chromatography should be used for identification, requiring no color fading or migration at high temperatures.
3. Secondary extrusion: plastic with high elastic modulus and low linear expansion coefficient shall be used to extrude into pipes of certain size, optical fibers shall be included and filled with moisture-proof and waterproof gel, and finally stored for several days (no less than two days).
4. Cable twisting: Twist several extruded optical fibers together with reinforcement units.
5. Squeezing the outer sheath of the optical cable: adding a layer of sheath to the twisted optical cable.