Numerical analysis of new output structures changed base on bus waveguide for 1.3 μm InAs/InGaAs quantum dot microdisk lasers on silicon

We design two types of output waveguide structures based on bus waveguide: waveguide overlapping with microdisk cavity and single-ended output bus waveguide. This is the first time that these two output structures have been designed for microdisk lasers on silicon. Three-dimensional finite-difference time-domain method is used to numerically analyze the optical mode characteristics of the microdisk lasers. The quality factor (Q-factor) and optical mode distribution of microdisk lasers are calculated in detail. The photoelectric properties of microdisk lasers with different output structures are simulated by rate equations, which provide evidence for lasing. For the first time, by comparing the differences between the two output structures, we identify the respective characteristics of these two structures: microdisk lasers with the waveguide overlaps with the microdisk cavity are suitable for vertical coupling devices when the notch width is 3.5 μm and the waveguide width is 1.5 μm. And the single-ended bus waveguide output structure changes the bus waveguide structure from two-ended to single-ended, which meets the requirement of laser directional output.