Modes of a semiconductor rectangular microcavity

The mode parameters of a rectangular cavity of a semiconductor laser emitting in the range from 850 to 880 nm are numerically calculated and analysed. Nearly quadratic microcavities with a side of length ~10 μm are considered. It is shown that, unlike a Fabry–Perot cavity, a rectangular cavity has a much more dense system of nonequidistant modes, which in principle cannot be interpreted as modes of an "efficient" Fabry–Perot cavity or a ring cavity. The maximum Q factor of modes in the cavities under study can exceed 10⁵, which corresponds to the reduced intracavity loss ~3 cm^-1. The radiation field of the cavity can be interpreted as the field of four coherent sources located at the cavity corners.