A Modified Flip-Chip LED Packaging Design With Enhanced Light Coupling Efficiency for Plastic Optical Fiber Networks

The explosive growth in the use of the Internet and multimedia applications in both the home and the office has fueled the requirement for high-bandwidth communication systems capable of processing huge volumes of data in a prompt and reliable manner. Plastic optical fiber (POF) has emerged as an ideal solution for meeting this requirement and is now specified by many architects as a simple, one-cable solution for home and office data communication networks. This study presents a modified flip-chip light emitting diode (LED) package for use in short-distance, POF-based communication systems. In contrast to the planar surface of the traditional design, the proposed LED package has a curved boundary surface between the underfill and the air. This boundary surface functions as a virtual lens, which focuses the light emitted by the LED into the acceptance cone of the optical fiber such that the amount of light coupled into the fiber core is maximized. The proposed design yields an average coupling efficiency of around 49.6% over an LED-optical core misalignment range of 0.4–3 mm. Furthermore, the curved boundary surface reduces the distance between the emitting source and the ambient environment; therefore, it improves the thermal dispersion efficiency of the LED package.