Design and optimization of unidirectional emitting multi-wavelength InAs/GaAs quantum dot microring lasers on silicon

We proposed a silicon-based monolithic integrated multi-wavelength InAs/GaAs quantum dot microring laser array with radially coupled waveguides. To achieve the stable multi-wavelength lasing of the laser array in the 1.3 μm band, the three-dimensional finite-difference time-domain method is used to numerically optimize structure parameters of the microring laser with a connected III–V waveguide. The results show that the microring laser can realize a stable mode TE50,1 with an outer-wall radius of 3.5 μm, a microring width of 1.0 μm, a cladding thickness of 1.50 μm, an etching depth of 5.255 μm and a waveguide width of 0.5 μm. The mode wavelength is 1302.43 nm with a quality factor of 20,093.6. The optical coupling efficiency from the laser to the waveguide is about 47.8%. Moreover, mode wavelengths can be adjusted by the microring radius. When the microring width is 1.0 μm, changing the outer-wall radius from 2.7 to 3.9 μm with an interval of 0.2 μm, the mode wavelength ranges from 1289.29 to 1307.28 nm with a step of about 3.00 nm. It is feasible to achieve multi-wavelength laser arrays for monolithic silicon integration, which facilitates the preparation of silicon-based III–V multi-wavelength integrated light sources for dense wavelength division multiplexing applications.