ELECTROLUMINESCENT DIODE WITH MODE EXPANDER

摘要

A semiconductor electro luminescent diode having a body of a semiconductor mater ial with the body having a pair of spaced opposed end surfaces, side surfaces and to p and bottom surfaces. The body includes therein an active layer which extends from one end s urface to a point spaced from the other end surface. The active layer is of a width narrower than the distance between the side surfaces. Also, the active layer has a portion adjacent the oth er end surface of the body which is tapered to come to a point. First clad layers of a material ha ving an index of refraction smaller than that of the active layer are at opposite sides of the ac tive layer and extend between the end of the active layer and the other end surface of the body. Secon d clad layers of a material having an index of refraction larger than that of the first clad layers but less than the index of refraction of the active layer are on the first clad layer. Radiation g enerated in the active layer and emitted from the pointed end of the active layer extends in area in th e portion of the second clad layer between the pointed end of the active layer and the other end of the body so that the area of the beam of radiation emitted from the -diode is larger than th e area of the beam formed in the active layer.