Two-Dimensional Photonic Crystals for Planar IR Laser Cavities With Vertical Beam Output

A semi-analytical 3D model has been developed to describe the modal structures of an infinite two-dimensional photonic crystal formed in a semiconductor laser waveguide heterostructure. Within the framework of the proposed simulation model, the relationship between the efficiency of laser mode light output through the surface and the geometric characteristics of the photonic crystal has been studied. As an example, we performed calculations and analysis of optical output losses in a waveguide heterostructure based on the AlGaAs/InGaAs material system. The study focused on square symmetry photonic crystals with simple geometric shapes, including circles and triangles. The results demonstrate that surface-emitting lasers designed in planar structures using photonic crystals based on circular holes have low radiation output efficiency. Efficient light output can be achieved by using triangular hole shapes with a fill factor greater than 0.1-0.2, while the symmetry of the triangular hole significantly influences the output efficiency. The fill factor also determines the mode discrimination and the conditions for single-mode or multi-mode operation. Structures incorporating regular triangular photonic crystals exhibit the highest output losses, while enhancing the mode overlap between the planar waveguide and the photonic crystal leads to an increase in output losses from 2 to 10 cm ${}^{\mathrm {-1}}$ .