At present, a number of LiDAR companies have adopted 1550nm fiber laser as the transmitting light source, which enables LiDAR to have higher transmitting power and laser frequency while ensuring human eyes safety. As a result, LiDAR detection range and accuracy could be improved, meeting the needs of long-distance detection(up to several km). Moreover, 1550nm fiber laser performs better in rainy and foggy climates, providing more robust perception for autonomous driving in expressway. The scheme of 1550nm fiber laser can fundamentally solve the problem of detection distance, but its high cost is the block of large-scale application.