On-chip laser technologies have seen rapid rise in demand by commercial applications including high compacity communications, light detection and ranging (LiDAR), augmented/virtual reality (AR/VR), quantum computing and communication, as well as other applications including medicine, spectroscopy, and environmental gas sensing. Previously, most on-chip lasers were operated at telecom wavelength, and usually lacked high performance in coherency, reconfigurability and spectrum coverage compared with bench-top lasers. In the past decade, there has emerged significant advance in on-chip laser technologies which overcome these limitations, leading to many new opportunities in integrated photonics. In this PIERS session, we invite distinguished researchers to cover the advance on these on-chip laser technologies, as well as discussing the requirements and challenges from the application end.