The transmission interface of the sfp optical transceiver inputs an electrical signal with a certain code rate, and after being processed by the internal driver chip. The modulated fiber optical signal of the corresponding rate is emitted by the driving semiconductor laser (LD) or light-emitting diode (LED). The optical signal is converted into an electrical signal by a photodetector diode, and an electrical signal of a corresponding code rate is output after passing through a preamplifier.