Optical modules can be divided into single-mode and multi-mode optical modules. Usually, single-mode is represented by SM, and multi-mode is represented by MM. ZR Cable introduced the resolution method in addition to these accidents.
ZR Cable Optical Module
1. Different wavelengths
Generally, the wavelength of multi-mode light is 850nm, and 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 serious inter-mode dispersion; while single-mode optical modules are mostly used for long-distance transmission such as LR, ER, and ZR. Under normal circumstances, the transmission distance of less than 2km is called a multi-mode module; the transmission distance of more than 2km is called a single-mode module.
Second, the application range is different
Multi-mode optical modules are mostly used in networks with relatively low transmission rates and relatively short transmission distances, such as local area networks, etc. Such networks usually have many nodes, many joints, many detours, large amounts of connectors and couplers, and units. The length of the fiber uses the characteristics of a large number of light sources, and the use of multi-mode optical modules can effectively reduce network costs;
Single-mode optical modules are mostly used in lines with long transmission distances and relatively high transmission rates, such as long-distance trunk transmission and metropolitan area network construction.
3. Different types of optical fibers
According to the transmission mode of light in the fiber, it is divided into: single-mode fiber and multi-mode fiber. Multimode fiber (Multimode Fiber, abbreviated as MMF) has two fiber diameters, 50/125 μm or 62.5/125 μm, and their transmission distances are different. In general, 50/125μm can transmit 550m in Gigabit environment, and 62.5/125μm can only transmit 330M.
A single-mode fiber (Single-mode Fiber, abbreviated SMF) has a fiber diameter of 9/125 µm. The main wavelengths of single-mode fiber are 1310nm and 1550nm. Optical fiber loss generally decreases with increasing wavelength. The loss at 1310nm is 0.35dB/km; the loss at 1550nm is 0.20dB/km.
Single-mode fiber is cheap, but single-mode equipment is much more expensive than comparable multi-mode equipment. Single-mode equipment typically operates on both single-mode fiber and multi-mode fiber, while multi-mode equipment is limited to operating on multi-mode fiber.
