HIGH-BRIGHTNESS, ALGAINP-BASED, VISIBLE LIGHT-EMITTING DIODE FOR EFFICIENT COUPLING WITH POF

A high-brightness light-emitting diode (LED) is fabricated using the A lGaInP based quaternary double heterostructure. The ring type electrod e is used in the top contact in order to spread the current efficientl y and also to enhance the coupling efficiency with the fiber, The fabr icated LED has a light output as high as 1.7 mW at the bias current of 100 mA, The far-field radiation divergences are found to be approxima tely 100 and 70 degrees for the LED's, with and without molding. These LED's offer coupling efficiency as high as 70% and 35%, with the step index (SI) plastic optical fiber (POF) after using the molded and hyb rid ball lens, respectively, The increases of the coupling efficiency are due to the use of the ring-shaped top electrode, concentrating the emission mostly at the center.