A monolithic integrated amplified feedback laser is experimentally demonstrated as a new solution to generate dual-mode lasing with a wide frequency tuning range covering the entire 60-GHz band. This laser consists of a complex-coupled distributed feedback laser (DFB) and an integrated feedback cavity formed by a phase section and an amplifier section. Different laser sections are integrated by a simple quantum well intermixing (QWI) technique.
By tuning the injection currents of the laser sections, the beating-frequency can be continuously tuned from 46.8 to 72 GHz with a 3-dB linewidth below 5 MHz. Benefit from the simple fabrication process and wide tuning range, the device will be a potential candidate for hybrid fiber-wireless access network and high frequency optical microwave generation.