A classification of optical fibers
Optical fiber is the abbreviation of optical fiber. But optical fiber is often simplified to fiber in communication system, such as fiber amplifier or fiber backbone.
In fact, optical fiber is a kind of media which is made of transparent material and cladding made of material whose refractive index is slightly lower than that of the core, and reflects the optical signal into the core through the cladding interface to make the optical signal propagate in the core.
There are many kinds of optical fibers. According to different uses, the required functions and performances are also different. But for the optical fiber used in CATV and communication, the design and manufacturing principles are basically the same.
Such as: 1;
② It has a certain bandwidth and small dispersion;
③ Easy wiring;
④ It is easy to be unified;
⑤ High reliability;
⑥ It’s easy to make.
Silicon dioxide (SiO2) is used as the main raw material to control the refractive index distribution of core and cladding according to different doping amount. Quartz (glass) series optical fiber, with the characteristics of low power consumption and broadband, has been widely used in cable TV and communication systems.
Triple infrared fiber
As the working wavelength of quartz series optical fiber developed in the field of optical communication, although it is used in a short transmission distance, it can only be used for 2pm. Therefore, it can work in the field of longer infrared wavelength, and the developed fiber is called infrared fiber.
Quadruple optical fiber
Composite fiber is made of SiO2 raw material and multi-component glass such as Na2O, b2o2 and K2O. The characteristics of composite fiber are that the softening point of multi-component glass is lower than that of quartz, and the refractive index difference between core and cladding is very large. The optical fiber endoscope is mainly used in medical business.
Pentafluoride optical fiber
Chloride fiber is made of fluoride glass. This kind of optical fiber material is also called ZBLAN (abbreviated as aluminum fluoride (ZrF4), barium cyanide (BaF2), lanthanum fluoride (LaF3), aluminum fluoride (a1f2), sodium cyanide (NAF) and other chloride glass materials). It mainly works in 2 ~ 10pm wavelength optical transmission services.
Six plastic clad fiber
Plastic clad fiber is a kind of step optical fiber, which is made of high-purity quartz glass and coated with plastic such as silica gel whose refractive index is slightly lower than that of quartz. Compared with quartz fiber, it has the characteristics of high core group and high numerical aperture (NA).
7. Plastic optical fiber
This is an optical fiber made of plastic (polymer) for both core and cladding. Early products are mainly used for decoration and light guide lighting and optical communication of short distance optical key path.
Eight single mode fiber
This means that in the working wavelength, only one propagation mode fiber can be transmitted, usually referred to as single mode fiber (SMF: single). At present, it is the most widely used optical fiber in CATV and optical communication.
Nine mode fiber
Multimode fiber (MMF: multi) is a kind of multi-mode fiber whose propagation mode is multi-mode according to the working wavelength. Compared with SMF, the transmission bandwidth is dominated by mode dispersion. In history, it was used for short distance transmission of cable TV and communication system.
When the operating wavelength of single-mode fiber is 1.3pm, the mode field diameter is about 9pm, and the transmission loss is about 0.3db/km. At this time, the zero dispersion wavelength is exactly at 1.3pm.
Dispersion flattened fiber
Dispersion shifted fiber (DSF) is a single-mode fiber with zero dispersion in 1.55pm band. The dispersion flattened fiber (DFF) is a kind of fiber which can achieve very low dispersion from 1.3pm to 1.55pm and almost zero dispersion.
Twelve birefringent fibers
Birefringent fiber is a kind of fiber which can transmit two orthogonal polarization modes in single-mode fiber. Because the phenomenon that the refractive index varies with the direction of bias is called birefringence.
13. Optical fiber resistant to adverse environment
The ambient temperature of communication optical fiber can be between – 40 ℃ and + 60 ℃, and the design is based on the premise of not being exposed to a large number of radiation. In contrast, the optical fiber that can work even at lower or higher temperature and under the harsh environment of high pressure or external force and exposure to radiation is called hard fiber.
14. Sealed coated optical fiber
In order to keep the mechanical strength and loss of optical fiber stable for a long time, inorganic materials such as silicon carbide (SIC), titanium carbide (TIC) and carbon (c) are coated on the glass surface to prevent the diffusion of water and hydrogen from the outside.
Fifteen carbon coated optical fiber
Carbon coated fiber (CCF) is an optical fiber coated with carbon film on the surface of quartz optical fiber. The mechanism is that the dense carbon film is used to isolate the surface of the optical fiber from the outside world, so as to improve the mechanical fatigue loss of the optical fiber and increase the loss of hydrogen molecules. CCF is a kind of sealed coating fiber (HCF).
Sixteen eccentric fiber
The core of standard optical fiber is set in the center of cladding, and the cross-section shape of core and cladding is concentric. However, due to different uses, there are also cases where the core position, core shape and cladding shape are made into different states or the cladding is perforated to form a special-shaped structure. Compared with standard optical fibers, these optical fibers are called heteromorphic optical fibers.
Seventeen luminescent fiber
The optical fiber is made of fluorescent material. It is a part of the fluorescence generated by radiation, ultraviolet and other light waves, which can be transmitted through the closed optical fiber.
18 core optical fiber
Usually, an optical fiber consists of a core region and a cladding region surrounding it. However, multicore fiber has multiple cores in a common cladding region. Due to the proximity of the cores, there are two functions.
Nineteen hollow optical fibers
Hollow fiber is a kind of hollow fiber used for optical transmission.
Editor in charge ajx