There are many types of optical fibers, depending on the purpose, the required functions and performance are also different. For cable television and communications, however, the principles of design and fabrication are essentially the same, such as:
① loss is small;
② has a certain bandwidth and small dispersion;
③ wiring is easy;
④ is easy to be integrated;
⑤ high reliability;
⑥ manufacturing is relatively simple;
⑦ cheap and so on.
The classification of optical fiber is mainly from working wavelength, refractive index distribution, transmission mode, raw materials and manufacturing methods to make a summary, mainly the following categories:
(1) Working wavelength: ultraviolet fiber, considerable fiber, near-infrared fiber, infrared fiber (0.85μm, 1.3μm, 1.55μm).
(2) Refractive index distribution: Step (SI)-type fiber, near-step fiber, gradient (GI)-type fiber, other (such as triangular, w-type, concave-type, etc.).
(3) Transmission mode: Single-mode fiber (including polarization-maintaining fiber, non-polarization-maintaining fiber), multimode fiber.
(4) Raw materials: quartz fiber, multicomponent glass fiber, plastic fiber, composite fiber (such as plastic cladding, liquid fiber core, etc.), infrared materials. According to the material can also be divided into inorganic materials (carbon, etc.), metal materials (copper, nickel, etc.) and plastic.
(5) Manufacturing methods: Pre-plastic has vapor phase axial deposition (VAD), Chemical vapor deposition (CVD), such as wire drawing method has a tube law (Rod intube) and double crucible pot method.