“…The bulk (GaInP) AL is positioned at a very short distance (50 nm) from the pcladding (note that the location of the active layer, bulk or Quantum Well, near the p-cladding is currently widely accepted for high-power semiconductor lasers [4,5,8,9,10,11]). As noted previously [1][2][3], in a waveguide of this type, unlike in most structures with Quantum Well based active layers, the AL itself contributes noticeably to the waveguiding properties of the structure, strongly affecting the shape of the mode. Thus, the thickness da of the active layer becomes an important and useful parameter in varying and potentially optimising the laser design and properties.…”