Benefiting from narrow-linewidth semiconductor lasers, various fields such as coherent optical communication, optical sensing and detection, and optical frequency synthesis are developing rapidly. Mass-produced integrated lasers with superior coherence are required in order to bring the advantages of semiconductor lasers to wider applications. We are dedicated to the research of highly coherent semiconductor lasers in integrated photonics, by optimizing the design and fabrication process of multiple material platforms. We have achieved mHz-level linewidth integrated lasers by using CMOS-compatible large-scale integrated fabrication, which will lead to unprecedented precision in ranging and time-frequency metrologies.