and 106 are also a part of the waveguide structure since their indices of refraction are lower than those of quantum well 109 and guiding layers 107 because the refractive index of n cladding 106 is higher than the refractive index of p cladding 110 the majority of the optical mode is tilted towards n cladding 106 and n substrate 102 in order to prevent leaking of the light into n substrate 102 having a refractive index higher than that of n cladding 106 n blocking layer 104 is disposed between said layers 102 and 106 the thicknesses and refractive indices of layers 102 112 are chosen such that even though the optical mode is tilted towards the n substrate the peak of the optical mode still resides in active region 108 so as to maximize the confinement factor defined above moreover the refractive indices of said layers are chosen so that the peak of the optical mode stays within active region 108 at thicknesses of the n cladding layer varying from 1 7 to 5 7 microns for ingaas algaas 980 nm lasers an exemplary method of manufacture is as follows the semiconductor layers are grown by molecular beam epitaxy or metal oxide.