We review the recent work of distributed-feedback (DFB) multi-wavelength semiconductor laser arrays (MWLAs) based on the reconstruction equivalent chirp (REC) technique. The experimental results show that the proposed MWLA has very high wavelength precision (<±0.1 nm), while the fabrication cost is low. Only one step of holographic exposure and another step of photolithography are required for grating fabrication. The packaging technique for a high-bandwidth analog DFB laser and laser array was developed. A directly modulated MWLA transmitter module was achieved. In addition, an improved MWLA with an integrated reflector was proposed and successfully applied in a radio-over-fiber system.