Title :
Fiber-Coupled Light-Emitting Diode With a Capillary-Bonded Hemispherical Lens
Author :
Zhu, L. ; Huang, S.Y. ; Lai, P.T. ; Choi, H.W.
Author_Institution :
Dept. of Electr. & Electron. Eng., Univ. of Hong Kong, Hong Kong, China
Abstract :
A hemispherical lens capillary-bonded to an InGaN flip-chip light-emitting diode (LED) is demonstrated to efficiently couple light to a plastic optical fiber. The BK-7 hemispherical lens is bonded onto a circularly shaped LED chip with inclined sidewalls cut by laser-micromachining, so that lateral emissions are effectively suppressed. Capillary bonding minimizes air-gap between chip and lens enabling transmission of evanescent waves, thus maximizing overall optical transmission. With the lens attached, emission divergence from the assembly is significantly reduced, diverting rays into the acceptance cone of the fiber. Fiber coupling efficiency as high as 53.8% has been demonstrated.
Keywords :
III-V semiconductors; bonding processes; capillarity; flip-chip devices; gallium compounds; indium compounds; laser beam machining; lenses; light emitting diodes; micromachining; optical fibres; wide band gap semiconductors; InGaN; capillary-bonded hemispherical lens; circularly shaped LED chip; evanescent wave transmission; fiber-coupled light-emitting diode; flip-chip light-emitting diode; laser-micromachining; optical transmission; plastic optical fiber; Light emitting diodes; Optical fiber communication; Optical fiber devices; Optical surface waves; Fiber coupling; light-emitting diode (LED);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2011.2170407
