公开(公告)号：US3877052A

公开(公告)日：1975-04-08

申请号：US42778573

申请日：1973-12-26

Applicant: BELL TELEPHONE LABOR INC

Inventor： DIXON RICHARD WAYNE ,  JOYCE WILLIAM BAXTER ,  RODE DANIEL LEON

IPC: G02B6/42 ,  H01L33/00 ,  H01L33/46 ,  H05B33/00

CPC classification number: H01L33/46 ,  G02B6/4204 ,  H01L33/00 ,  H01L33/385

Abstract: A semiconductor light-emitting diode (LED), which is substantially transparent to its own generated radiation, is coated with a reflecting layer having an exit aperture for transmission of optical radiation, for example, to an optical fiber. The reflecting layer includes a layer of dielectric in contact with the semiconductor, the dielectric layer itself being coated with an optically reflecting metal layer. The dielectric layer is made sufficiently thick to prevent the evanescent waves (of the totally internally reflected light in the semiconductor) from contacting the metal, thereby affording very close to 100 percent optical reflection of the optical rays in the semiconductor which are incident on the dielectric at greater than the critical angle. In addition, a significant portion of the semiconductor-dielectric interface is rough, thereby scattering (randomizing) the totally internally reflected rays in the semiconductor, which rays otherwise would have no chance of being accepted into the optical fiber. Thus, the overall coupling efficiency of optical radiation from the diode to the optical fiber is enhanced.