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1. Transmission of single-mode optical cable


The single-mode optical cable is actually used for transmission with an intermediate fiber core, known as an optical fiber. Single mode optical cable is composed of optical fiber, outer sheath, and intermediate medium. In fiber optic communication, single-mode fiber (SMF) is a type of fiber that directly transmits optical signals in transverse mode. Single mode fiber can operate at a data rate of 100M/s or 1 G/s, with a transmission distance of at least 5 kilometers.


Single mode fiber: The central glass core is very thin (usually 9 or 10 μ m in diameter), and can only transmit one mode of fiber. Therefore, its inter modal dispersion is very small and suitable for remote communication, but there are still material dispersion and waveguide dispersion. Therefore, single-mode fibers have high requirements for the spectral width and stability of the light source, that is, the spectral width should be narrow and the stability should be good.


2. Transmission of multimode optical cable


Multimode optical cables are mainly used for short distance fiber optic communication, such as in buildings or campuses. The typical transmission speed is 100M/s, the transmission distance can reach 2km, 1 G/s can reach 1000m, and 10 G/s can reach 550m. There are two types of refractive indices: gradient refractive index and step refractive index.


Multimode fiber: a fiber that transmits multiple modes at a given operating wavelength.


According to its refractive index distribution, it can be divided into abrupt and gradual types. Due to the transmission of hundreds of modes in multimode optical fibers, the propagation constants and group rates of each mode are different, resulting in a narrow bandwidth, high dispersion, and high loss of the fiber, which is only suitable for medium to short distance and small capacity fiber communication systems.