Optical module and SOA gain control method

According to an optical module and an SOA gain control method provided by the invention, an optical receiving sub-module comprises an optical amplification assembly, an optical receiving assembly and a trans-impedance amplifier, the optical amplification assembly comprises the semiconductor optical amplifier, and incident light signals are transmitted to the light receiving assembly after being gained through the semiconductor light amplifier, and then are converted into electric signals through the light receiving assembly and the trans-impedance amplifier in sequence; and an MCU obtains detection signals output by a sampling unit under the current amplification gain of the semiconductor optical amplifier, compares the obtained detection signals with a large light threshold and a small light threshold corresponding to the current working current, and adjusts the amplification gain of the semiconductor optical amplifier according to the comparison result. According to the optical module and the SOA gain contr