Fig. 5: Directional couplers.
From: AlGaN/AlN heterostructures: an emerging platform for integrated photonics
a Optical microscope image of an AlGaN directional coupler. b Schematic illustration of the geometry, where the relevant parameters are presented. c Output intensity ratios across various coupling lengths and gap sizes, enabling the determination of the coupling constant for gaps measuring 230 and 330 nm.
