We believe everyone now has a certain understanding of the transmission distance of optical modules, which can be divided into short-distance, medium-distance, and long-distance optical modules. Generally, the transmission distance of short-distance optical modules is within 2 km, the transmission distance of medium-distance optical modules is 10-20 km, and the transmission distance of long-distance optical modules is above 30 km. Some people define long-distance optical modules as those above 40 km. No matter how it is defined, it is necessary to ensure that the line and the optical module meet the standard indicators to avoid signal interruption and other issues. As a professional 100g qsfp28 supplier, we are familiar with relative technologies including cisco 100g compatibility matrix.
When manufacturers produce optical modules, they generally follow standard specifications to ensure that the optical module's transmitting power and receiving sensitivity are within the normal standard range to achieve the transmission distance. Here we have a formula that shows which factors affect the transmission distance. Loss-limited distance = (transmitting power-receiving sensitivity) / fiber attenuation. From this formula, it can be seen that the limit condition of the transmission distance is not only limited to the optical power and sensitivity of the optical module but also related to the actual line loss used. Taking the 100km 10G single-mode optical module as an example, the normal laboratory line setup is 2 rolls of 40km plus one roll of 20km fiber, connected with attenuators in the middle, and the loss is 0.22db. Therefore, if the 100km optical module is used on a line with a loss of more than 22db, there may be packet loss during transmission. 100g optical modules are for sale. A customer asked that they had a 70km line, but the line loss exceeded 26db, so even if they used our 100km 10G optical module, it could not guarantee the normal transmission of optical signals. By achieving a transmitting power of 2db and a receiving sensitivity of -24db, losses can be compensated. However, if the line has too much loss or if the optical module is overloaded for an extended period, the link may still have problems. We suggest customers add optical amplifiers or repeaters for better results.