Notice on optical power of Optical module.cicso sfp transceivers module

The unit of optical power is dbm, which is listed in the manual of fiber optic transceivers or switches for its luminous and receiving optical power. Usually, the luminous power is less than 0dbm, and the minimum optical power that the receiving end can receive is called sensitivity. The unit of subtracting sensitivity from the maximum optical power that can be received is db (dbm dbm=db), which is called dynamic range, The luminous power minus the receiving sensitivity is the allowable optical fiber attenuation value. The value of the actual luminous power minus the actual received optical power during the test is the optical fiber attenuation (db). The optimal value of the optical power received by the receiving end is the maximum optical power that can be received - (dynamic range/2), but generally it is not so good. Since the dynamic range of each optical transceiver and Optical module is different, the specific allowable attenuation of the optical fiber depends on the actual situation, Generally speaking, the allowable attenuation is around 15-30db. Some manuals may only have two parameters: luminous power and transmission distance. Sometimes, they may indicate that the transmission distance calculated based on the attenuation of the fiber per kilometer is mostly 0.5db/km. Dividing the minimum transmission distance by 0.5 is the maximum optical power that can be received. If the received optical power exceeds this value, the optical transceiver may be burned out. Dividing the maximum transmission distance by 0.5 is the sensitivity. If the received optical power falls below this value, the link may not be connected. There are two ways to connect optical fibers, one is fixed connection and the other is movable connection. Fixed connection is fusion connection, which uses specialized equipment to discharge and melt the optical fibers to connect two segments together. The advantage is low attenuation, while the disadvantage is complex and flexible operation. Active connection is usually connected to the tail fiber on ODF through connectors, with the advantage of simple operation and flexibility. The disadvantage is high attenuation, Generally speaking, the attenuation of an active connection is equivalent to one kilometer of optical fiber. The attenuation of optical fiber can be estimated as follows: including fixed and active connections, the attenuation of optical fiber per kilometer is 0.5 dB. If there are relatively few active connections, this value can be 0.4 dB. Pure optical fiber does not include active connections, which can be reduced to 0.3 dB. The theoretical value of pure optical fiber is 0.2 dB/km; For insurance purposes, 0.5 is generally preferred. The optical fiber test TX and RX must be tested separately. In the case of single fiber, only one fiber is used, so of course, only one test is needed. According to the production company, the realization principle of single fiber is Wavelength-division multiplexing, but I think the possibility of using optical fiber coupler is higher. What is an optical power meter used to measure absolute optical power or the relative loss of optical power through a section of optical fiber. In fiber optic systems, it is very similar to a multimeter in electronics. In fiber optic measurement, optical power meters are commonly used for heavy loads. By measuring the absolute power of the transmitting device or optical network, an optical power meter can evaluate the performance of the optical device. The combination of an optical power meter and a stable light source can measure connection loss, verify continuity, and help evaluate the transmission quality of fiber optic links. To select a suitable optical power meter for the specific application of the user, attention should be paid to the following points: 1. Select the optimal probe type and interface type. 2. Evaluate calibration accuracy and manufacturing calibration procedures to match your fiber optic and connector requirements. 3. Ensure that these models are consistent with your measurement range and display resolution. 4. DB function for direct insertion loss measurement.