High-efficiency short-cavity III-V-on-Si C-band DFB laser diodes

In this paper, we demonstrate a high-efficiency, short-cavity heterogeneously integrated C-band DFB laser on a Si waveguide realized using adhesive bonding. First, simulation results regarding the integrated cavity design are discussed. In order to decrease the optical loss inside the cavity, we designed a configuration where the optical mode inside the laser cavity is predominantly confined to the Si waveguide underneath. Then, the fabrication technology of the demonstrated device is explained. Finally, we discuss the measured static and dynamic characteristics of the integrated laser. Up to 13% wall plug efficiency is achieved for a 200 mu m long DFB laser diode at 20 degrees C. Up to two times 6 mW of optical power is coupled into the silicon waveguide and more than 44 dB side-mode suppression ratio is obtained. In addition, the dynamic characteristics of the device are demonstrated by non-return-to-zero on-off keying modulation at 20 Gb/s and the transmission over a 2 km long optical fiber.