The difference between single mode and multimode fiber

Multimode fiber has a certain market share in fiber optic cabling of intelligent buildings because of the severe dispersion, large attenuation, narrow available bandwidth and high cost. When the multimode fiber optic cable is used for video picture transmission, it can only satisfy the transmission interval of up to 3~5km, and has a large constraint on the bandwidth (for analog modulation) and transmission rate (for digital) of the video optical transceiver. Suitable for short-distance, small-capacity, and simple use. In particular, the use of non-compact digital optical transceivers with high-rate transmission greatly limits the transmission interval and capacity due to the influence of dispersion.
Single Mode Fiber: The center glass core is very thin (the core diameter is generally 9 or 10 μm) and can only transmit one form of fiber. Therefore, the dispersion between modes is small, suitable for long-distance communication, but there is also data dispersion and waveguide dispersion, so that single-mode fiber has high requirements on the spectral width and stability of the light source, that is, the spectral width is narrow and stable. It’s better. Later, it was found that in the interest of 1.31μm wave, the data dispersion and waveguide dispersion of single-mode fiber are positive and negative, and the size is just the same.
According to the form of light waves transmitted in the fiber, they can be divided into two categories:
Single-mode only transmits the main mode, and the light is transmitted only along the inner core of the fiber. This completely avoids the form dispersion, making the transmission band of the single-mode fiber wide, so it is suitable for large-capacity, long-interval fiber transmission. Single mode fibers use a wavelength of light of 1310 nm or 1550 nm.
Multi-mode fiber (Multi-Mode) has multiple forms of transmission in the fiber at a certain operating wavelength (850 nm / 1310 nm). Because of the dispersion, the fiber has poor transmission performance and narrow frequency band. The transmission capacity is small and the interval is short. Because of the lack of multi-mode bare fiber capacity supply in domestic shopping malls in 2015, shopping malls are very tight.