Dual-wavelength distributed feedback laser for photonic microwave generation

We present a compact and simple approach to realize dual-wavelength distributed feedback laser by introducing two distributed feedback (DFB) lasers, in series, with different ridge widths and uniform gratings. Each laser emits single longitudinal mode and an electro-absorption modulator (EAM) has been integrated within the laser cavity in order to stabilize the beating signal by nonlinear four-wave mixing and lock phase of the two optical signals. A stable 74.9GHz beating signal was obtained within a wide range of bias parameters in terms of drive currents to two DFB lasers. By down-conversion technique, the beating signal has been observed by electrical spectrum analyzer.