Optical cable manufacturers tell you that outdoor optical cables are mainly used for interconnection between buildings and remote networks. Due to the installation environment, it has stronger pressure resistance, corrosion resistance and greater tensile strength than indoor optical cables. And a thicker protective layer, mostly armored. Outdoor fiber optic cables have single mode and multimode distribution.
The single-mode outdoor optical cable core is about 10μm, the propagation path is single, there is no dispersion, and the light source is mostly a laser or a laser diode, and the attenuation of the optical signal is much smaller than that of the multi-mode outdoor optical cable. For example, the optical signal attenuation of a multimode outdoor cable may reach 50% at a distance of 1000 meters, while the optical signal attenuation of a single mode outdoor cable at the same distance is only 6.25%.
The multimode outdoor optical cable is named because it divides the propagation mode into multiple modes according to the working wavelength. The core diameter is 50μm, and the light source is mostly LED or VCSEL (Vertical Cavity Surface Emitting Laser). Due to the variety of transmission paths, the transmission bandwidth is dominated by modal dispersion compared to single mode outdoor cables. Since the multimode outdoor optical cable core diameter is larger than that of the single mode outdoor optical cable and is easier to combine with LED and other light sources, it has advantages in many LANs. Therefore, multimode outdoor cables are often used in short-distance outdoor network connections.
The transmission distance between the single-mode outdoor optical cable and the multi-mode outdoor optical cable is often the decisive factor. When the transmission distance is short, the multi-mode outdoor optical cable should be the first choice, because the LED transmitting and receiving device used is far lower in cost. The laser required for a single mode. The effective distance of the multimode outdoor cable from the transmitting end to the receiving end is about 8km, so when the transmission distance is greater than 8km, the single mode outdoor optical cable should be selected.
Difference between single mode outdoor cable and multimode outdoor cable
1, look at the cable packaging
The outdoor optical cable supply standard length is generally 1km, 2km, 3km, 4km or custom length. When viewing the outer packaging of the outdoor optical cable, it is necessary to determine whether the outer packaging has obvious signs such as the number of meters, the name of the factory, and the type of optical cable. Is there a cable test record in the package?
2, look at the cable sheath
The indoor optical cable sheath is generally made of polychloroethylene, or flame retardant polychloroethylene, or low-smoke halogen-free material. The high quality outdoor cable sheath is flexible and easy to peel off.
3, look at the cable to strengthen the metal skin
Most of the outdoor optical cables are armored optical cables with a reinforced metal layer. The metal layer needs to have characteristics such as no increase in hydrogen loss, no rust, and high strength. Therefore, the metal layer is grayed on the phosphatized surface.
4, look at the cable core
The core part of the outdoor optical cable is its core. The multimode and single mode of the optical cable, OS2/OM1/OM2 and other characteristics are determined by the core, and the quality of the core plays a decisive role in the network connection. Therefore, pay special attention to the core of the cable when purchasing outdoor cables.
