Heterointegrated III-V/Si Distributed Feedback Lasers

With an ever-growing transmission data rate, electronic components reach a limit silicon photonics may overcome. This technology provides integrated circuits in which light is generated within hybrid III-V/Si lasers and modulated to transmit the desired information through silicon waveguides to input/output active/passive components such as wavelength (de-)multiplexers, fiber couplers and photodetectors. Nevertheless, high aggregate bandwidth through wavelength division multiplexing demands for spectrally narrowband lasers with high side-mode suppression ratio (SMSR). Distributed feedback (DFB) lasers offer such a great selectivity. We report hybrid III-V on Silicon DFB lasers emitting at 1550nm and 1310nm. The III-V material is wafer-bonded to patterned silicon-on-insulator (SOI) wafers. The laser cavity is obtained by etching a grating in the silicon, while silicon adiabatic tapers are used to couple light from/to III-V waveguides to/from the passive silicon circuitry, in order to maximize the laser available gain and output power. Gratings are either etched on the top of the silicon waveguide or on its sides, thus relaxing the taper dimension constraint. At 1550nm, the investigated device operates under continuous wave regime with a room temperature threshold current of 70mA, an SMSR as high as 45dB and an optical power in the waveguide higher than 40mW. At 1310nm, a threshold current of 35mA, an SMSR of 45dB and an optical power coupled into a single-mode fiber higher than 1.5mW are demonstrated.