Divided into single mode fiber and multimode fiber acco […]
Divided into single mode fiber and multimode fiber according to the transmission mode of optical fiber
Single mode fiber
This refers to an optical fiber that can only transmit one propagation mode at its operating wavelength. It is often referred to simply as single-mode optical fiber.
(SMF: Single Mode Fiber). At present, it is the most widely used optical fiber in cable television and optical communication.
Because the core of the fiber is very fine (about 10μm) and the refractive index is in a stepwise distribution, when the normalized frequency is V
When the number is <2.4, theoretically, only single mode transmission can be formed. In addition, SMF has no multi-mode dispersion and not only transmission band
The wider range of more mode fibers, plus the sum of the material dispersion and structural dispersion of the SMF, cancels out the composite characteristics
Zero dispersion characteristics make the transmission band wider.
In the SMF, there are many types of differences due to the difference in dopants and manufacturing methods. Depressed cladding fiber (DePr-
Essed Clad Fiber), whose cladding forms a double structure with cladding adjacent to the core, which is more reflective than outer cladding
The rate is still low. In addition, there is a matching cladding fiber, the refractive index of the cladding is evenly distributed.