Frequency noise reduction of semiconductor lasers using electrical feedback from an optical frequency discriminator is an efficient and simple approach to realize narrow linewidth lasers. These lasers are of great interest for applications such as LIDAR, RF photonics and interferometric sensing. In this paper, we review the technological choices made by TeraXion for the realization of its Narrow Linewidth Laser modules. The method enables to decrease the linewidth of DFB lasers from several hundreds of kHz to a few kHz. We present the work in progress to integrate such system into a miniature package and to incorporate advanced functionalities such as multi-laser phase locking.