The module integrates a high-speed low-noise analog photoelectric balance detector and a preamplifier small-signal fiber amplifier. In the fabrication process, the splitting ratio and length of the coupler are strictly controlled to further improve the common mode rejection ratio. The preamplifier fiber amplifier uses a special amplifier structure to amplify weak backscattered light. It has the characteristics of low ASE and small NF, and can improve the optical signal-to-noise ratio. The module is suitable for optical fiber sensing, laser wind radar and other fields.