Compound Fiber is made from SiO2 raw material, and then appropriately mixed with oxides such as sodium oxide (Na2O), boron oxide (B2O3), potassium oxide (K2O) and other oxides to make a multi-component glass fiber, which is characterized by multi-component glass It has a lower softening point than quartz glass and a large difference in refractive index between the core and the cladding. Fiber optic endoscopes mainly used in medical services.
Fluoride Fiber is an optical fiber made of fluoride glass. The representative of fluoride fiber is ZBLAN fiber. Its raw materials are zirconium fluoride (ZrF2), barium fluoride (BaF2), lanthanum fluoride (LaF3), aluminum fluoride (AlF3), sodium fluoride (NaF) and other fluorides. Combine according to a certain ratio. The light transmission is mainly realized at the wavelength of 2～10μm. Because ZBLAN fiber has the possibility of ultra-low loss fiber, the feasibility development for long-distance communication fiber is underway. For example, its theoretically lowest loss can reach 10^-2～10^-3 dB at a wavelength of 3μm. /km, while the quartz fiber is between 0.15~0.16dB/Km at 1.55μm. Because ZBLAN fiber is difficult to reduce the scattering loss, it can only be used in the temperature sensor of 2.4 ~ 2.7 μm and thermal image transmission, and it has not been widely used. Recently, in order to use ZBLAN for long-distance transmission, a 1.3μm praseodymium-doped fiber amplifier (PDFA) is being developed.
Plastic coated optical fiber
Plastic Clad Fiber (Plastic Clad Fiber) is a step-type fiber in which high-purity silica glass is used as the core, and plastic such as silica gel with a slightly lower refractive index than silica is used as the cladding. Compared with silica fiber, it has the characteristics of thick core and high numerical aperture (NA). Therefore, it is easy to combine with the light-emitting diode LED light source, and the loss is also small. Therefore, it is very suitable for local area network (LAN) and short-distance communication.