Patent attributes
A device contains at least one leaky waveguide layer, and has a transparent substrate, having a higher refractive index. The leakage loss of the waveguide exceeds the modal gain needed to initiate waveguide lasing. The leaky emission is going into the substrate at a certain angle, is reflected from the substrate back surface, and returns towards the leaky waveguide layer exhibiting constructive or destructive interference. As the leakage emission is returned to the active medium, the low threshold current density lasing is possible. As the leakage angle is defined for a given wavelength, interference enables lasing only at certain wavelengths making it possible to realize wavelength-selectivity. The lobes of the output emission can be made arbitrarily narrow by increasing the thickness of the substrate and the exit angle of the lobes is controlled by the leakage angle of the waveguide.
