1. Classified by material composition
Glass optical fiber: The core and cladding are made of glass, with low loss, long transmission distance and high cost.
Rubber-sheathed silicon fiber: the core is glass, the cladding is plastic, the characteristics are similar to glass fiber, and the cost is low.
Plastic optical fiber: The core and cladding are made of plastic, which has high loss, short transmission distance, and low price. It is mostly used for short-distance transmission at home appliance level.
2. Classified by transmission point mode
Fiber is divided into single-mode fiber SMF, multimode fiber MMF.
Single-mode fiber: uses a solid-state laser as the light source, allowing only one beam of light to propagate. The fiber core is thin, the transmission frequency is wide, the capacity is large, and the transmission distance is long. The PMD standard recommends that the core diameter is 8-10um, and the cladding diameter is 125um, and the commonly used one is 8.3/125um.
Multimode fiber: LEDs are used as light sources. Multiple beams of light are allowed to propagate simultaneously in the fiber, resulting in mode dispersion. The core wire of the multimode fiber is thick, the transmission speed is low, the distance is short, and the overall performance is poor, but the cost is low. The core diameter is 50-200um, and the cladding range is 125-230um.
In applications where optical cables are used to interconnect multiple nodes, the unidirectional characteristics of optical fibers must be considered. If two-way communication is to be performed, double-strand optical fibers must be used. Optical multiplexers arise from the need to multiplex and multiplex light of different frequencies.
3. According to the working wavelength
Optical fibers transmit light waves. The wavelength range of light is: the visible light part has a wavelength of 390-760nm, the part greater than 760nm is infrared light, and the part less than 390nm is ultraviolet light. Infrared light is used in optical fiber communication.
According to the working wavelength of the optical fiber, there are short-wavelength optical fibers, long-wavelength optical fibers and ultra-long-wavelength optical fibers. The working wavelength of multimode fiber is short wavelength 850nm and long wavelength 1300nm, and the working wavelength of single mode fiber is long wavelength 1310nm and ultra long wavelength 1550nm.