Transmit power is the power at which the transmitter of an optical transceiver module transmits optical signals in dBm. Transceivers are manufactured to meet the specifications (usually of the IEEE standards) and ranges represent the values that the part can operate within. However, in practical use, we adopt the average Tx power. The average transmission optical power refers to the optical power output by the light source at the. When we receive an optical module, we can observe some basic parameters of the optical module from the label, such as the encapsulation form, rate, wavelength, and transmission distance.