Fiber Module Single Mode Multimode Difference

　　Single-mode and multi-mode in fiber optic modules mainly refer to the types of fibers connected to fiber optic modules, which are significantly different in several aspects.

　　First, fiber type and fiber diameter

　　Single-mode optical module: using single-mode fiber (SMF) as the transmission medium, the fiber diameter is generally 9/125 μm.

　　Multimode optical module: Multimode fiber (MMF) is used as the transmission medium, and the fiber diameter is generally 50/125 μm or 62.5/125 μm.

　　Operating wavelength

　　Single-mode optical modules: operating wavelengths are generally 1310nm, 1550nm, etc.

　　Multimode optical module: The operating wavelength is generally 850nm.

　　III. Transmission distance

　　Single-mode optical modules: Often used for long-distance transmission, the transmission distance can reach tens to hundreds of kilometers, depending on the type and performance of the optical module. For example, some single-mode optical module products can reach up to 120km or 150 to 200km.

　　Multi-mode optical modules are mostly used for short-distance transmission, and the transmission distance is usually between a few hundred meters and several kilometers. For example, some multi-mode optical module products have a maximum distance of about 550m, while multi-mode optical modules are more commonly used below 2km.

　　IV. Bandwidth and signal attenuation

　　Single-mode optical module: Wide bandwidth, can support high-speed, high-capacity data transmission, with small signal attenuation and high signal transmission quality in optical fibers. Suitable for scenarios requiring long-distance and high-speed transmission such as core backbone networks.

　　Multimode optical module: The bandwidth is relatively narrow, the signal attenuation is large, and the signal transmission quality in the optical fiber is relatively low. However, the multimode optical fiber system has the advantages of low cost, easy installation and maintenance, and is suitable for short-distance transmission scenarios such as access layer and convergence layer networks.

　　Light sources and optical devices

　　Single-mode optical module: The light source is generally a LD (laser diode) or a narrow spectral line LED, and the light emitting devices are DFB, EML, FP, etc.

　　Multimode optical module: The light source is a Light Emitting Diode (LED) or a laser (such as VCSEL), and the light emitting device of the multimode fiber module is a VCSEL.

　　VI. Scope of application

　　Single-mode optical modules are mostly used in lines with relatively high transmission rates and relatively long distances, such as metropolitan area network construction, connection between data centers, and backplane transmission of wireless communication base stations.

　　Multi-mode optical modules are mostly used for short-distance transmission, such as access layer and convergence layer networks in buildings and campus networks. At the same time, they are also suitable for data communication fields (such as Ethernet, FDDI, ATM, etc.), storage area networks (SAN) and local area networks (such as enterprise intranets, campus networks, etc.) transmission.

　　VII. Cost

　　Single-mode optical module: Due to the relatively complex fabrication process of single-mode optical fiber, the cost of single-mode optical module is relatively high.

　　Multimode optical module: The fabrication process of multimode optical fiber is relatively simple, and the cost of multimode optical module is relatively low.

　　In summary, there are significant differences between single-mode optical modules and multi-mode optical modules in terms of fiber type, operating wavelength, transmission distance, bandwidth and signal attenuation, light source and optical device, application range and cost. When selecting optical modules, comprehensive consideration should be made according to actual application requirements and fiber transmission conditions.