The transmission distance of the optical module is divided into short-distance, medium-distance and long-distance. Single-mode optical transceivers are connected to single-mode optical fibers for medium and long-distance transmission, and multi-mode optical transceivers are connected to multi-mode optical fibers for short-distance transmission. But how does it calculate?
Optical fibers are necessary in optical transmission services, but there must be some loss during the transmission process. It generally refers to optical fiber attenuation. There are three main factors that affect the distance of optical transmission: transmitted optical power, receiving sensitivity, and optical fiber attenuation. The attenuation of the optical fiber is also related to optical fiber selected. Generally, the single-mode fiber is G.652, and the loss per kilometer at the 1310nm working wavelength is about 0.35db, and at the 1550nm is about 0.22db. Loss limited distance = (transmitting optical power-receiving sensitivity) / fiber attenuation. So now it is easy to calculate the limit transmission distance of the optical module. Take the ordinary Gigabit optical module as an example, the optical power is -3~-9db, the receiving sensitivity is -3~-22db, and the limit value is -3-(-22)=18db, 18db÷0.35db/km=51.428km, That is, the transmission distance of Gigabit 1310nm is up to 51km when only considering fiber loss, but in our actual application, there are other losses in addition to fiber loss, including bending loss, splicing loss, connection or coupling loss, connectors and splices. The insertion loss is not calculated. Therefore, removing the external loss part, the Gigabit 1310nm optical module can transmit as far as 40km.
WHGearlink, as a professional optical module manufacturer, provides high-quality optic fiber transceiver with reasonable fiber optic transceiver price. In order to prevent signal instability, packet loss and other phenomena in optical transmission, we will not take the limit distance.