Abstract: A vertical-cavity surface-emitting semiconductor laser has a substrate, a lower DBR structure portion having a plurality of layers provided on the substrate, a semiconductor buried structure portion provided over the lower DBR structure portion having at least one layer with buried therein an active layer, and an upper DBR structure portion having a plurality of layers provided over the semiconductor buried structure portion including the active layer. The active layer, at least one layer arranged over the active layer and at least one layer arranged beneath the active layer constitute an optical resonator region and each of the layers constituting the optical resonator region has an effective refractive index higher than respective effective refractive indices of other layers in the upper and lower DBR structure portions and a refractive index of the at least one layer constituting the semiconductor buried structure portion.

Abstract: A vertical-cavity surface-emitting semiconductor laser has a substrate, a lower DBR structure portion having a plurality of layers provided on the substrate, a semiconductor buried structure portion provided over the lower DBR structure portion having at least one layer with buried therein an active layer, and an upper DBR structure portion having a plurality of layers provided over the semiconductor buried structure portion comprising the active layer. The active layer, at least one layer arranged over the active layer and at least one layer arranged beneath the active layer constitute an optical resonator region and each of the layers constituting the optical resonator region has an effective refractive index higher than respective effective refractive indices of other layers in the upper and lower DBR structure portions and a refractive index of the at least one layer constituting the semiconductor buried structure portion.

Abstract: A vertical-cavity surface-emitting semiconductor laser has a substrate, a lower DBR structure portion having a plurality of layers provided on the substrate, a semiconductor buried structure portion provided over the lower DBR structure portion having at least one layer with buried therein an active layer, and an upper DBR structure portion having a plurality of layers provided over the semiconductor buried structure portion comprising the active layer. The active layer, at least one layer arranged over the active layer and at least one layer arranged beneath the active layer constitute an optical resonator region and each of the layers constituting the optical resonator region has an effective refractive index higher than respective effective refractive indices of other layers in the upper and lower DBR structure portions and a refractive index of the at least one layer constituting the semiconductor buried structure portion.

Abstract: A superlattice structure composed of at least two kinds of crystal layers, such as semiconductor layers, being different in bandgap, being combined alternately with each others, and the physical parameters of the layers being designed so that phase differences of reflected waves of injected electrons or holes are substantially equal to .pi. multiplied by an odd numbered integer so that the energy potential barrier height is effectively increased. When used in semiconductor lasers, it allows the confining efficiency of injected carriers to be noticeably improved.