Optical modules can be divided into single-mode and multi-mode optical modules, usually represented by SM for single-mode and MM for multi-mode. In addition to these, Mshine Optics introduces resolution methods.
1, Different wavelengths
The general wavelength of multimode light is 850nm, while the wavelength of single-mode light is mainly 1310nm and 1550nm. Multi mode optical modules can only be used for short distance transmission (SR) due to severe inter mode dispersion; Single mode optical modules are mostly used for long-distance transmission such as LR, ER, ZR, etc. Usually, a transmission distance of less than 2km is called a multimode module; A transmission distance of over 2km is called a single-mode module.
2, Different application ranges
Multimode optical modules are commonly used in networks with relatively low transmission rates and short transmission distances, such as local area networks. These networks typically have many nodes, joints, bends, a large amount of connectors and couplers, and a large number of light sources per unit fiber length. The use of multi-mode optical modules can effectively reduce network costs;
Single mode optical modules are commonly used in long-distance and relatively high transmission speed lines, such as long-distance trunk transmission, urban area network construction, etc
3, Different types of optical fibers
According to the transmission mode of light in optical fibers, it can be divided into single-mode fibers and multi-mode fibers. Multimode Fiber (MMF) with a diameter of 50/125 μM or 62.5/125 μM, There are two types of m, and their transmission distances are different. 50/125μM in a typical gigabit environment Can transmit 550m, 62.5/125 μM can only transmit 330M.
Single mode fiber (SMF) with a diameter of 9/125 μ M. The main wavelengths of single-mode optical fibers are 1310nm and 1550nm. The fiber loss generally decreases with increasing wavelength, with a loss of 0.35dB/km at 1310nm; The loss at 1550nm is 0.20dB/km.
Single mode fiber is cheap, but single-mode equipment is much more expensive than similar multimode equipment. Single mode devices can typically operate on both single mode and multimode fibers, while multimode devices are limited to operating on multimode fibers.
