Edge emitting, light-emitting diode

Claim 1

In a light emitting diode of the edge-emitting type comprising a plurality of contiguous semiconductor layers one of which forms an active layer with a p-n junction thereat and into which carriers are injected when a bias voltage is applied and from which electromagnetic radiation is produced, means for applying said bias voltage to at least a portion of said p-n junction; and means to establish a transverse optical cavity for allowing efficient propagation of optical radiation in a direction parallel to said active layer when said bias voltage is applied across said junction with electromagnetic radiation being emitted from said diode at an end surface thereof, said means comprising: a first confining layer of n-type semiconductor material of a first composition located within said optical cavity contiguous with said active layer for confining carriers in said active layer and having such a thickness that said electromagnetic radiation that leaves said end surface from said first confining layer at an exit angle within the numerical aperture of a receiving optical fiber travels through said first confining layer with no more than one reflection by another layer of said diode thereby minimizing the amount of electromagnetic energy absorbed; and a second confining layer of p-type semiconductor material of a second composition located within said optical cavity contiguous with a surface of said active layer not in contact with said first confining layer for confining carriers in said active layer and having such a thickness that said electromagnetic radiation that leaves said end surface from said second confining layer at an exit angle within said numerical aperture of said receiving optical fiber travels through said second confining layer with no more than one reflection by another layer of said diode thereby minimizing the amount of electromagnetic energy absorbed; said first and second confining layers having different compositions, said first confining layer and said active layer and said second confining layer and said active layer having sufficient compositional differences to confine electrical carriers to said active layer, said compositions of said confining layers and said active layer thickness being selected so that the confinement factor, γ, is approximately zero and substantially all of said electro-magnetic radiation produced in said active layer leaves said active layer and enters said first and second confining layers.