Analysis and optimization of chip-to-fiber coupling interfaces for micro-LED-based optical communications

Micro-light-emitting diode (micro-LED) arrays have become highly promising transmitters in chip-to-chip optical communications based on fibers, due to their high bandwidth, low power consumption and compact sizes. However, micro-LED-to-fiber coupling loss remains a critical challenge that limits practical integration. This study focuses on the development and application of simulation methodologies to optimize the interface between optical fiber bundle and micro-LED array. Using Finite-Difference Time-Domain method, the study examines the influences of gap distance, fiber core diameter and lateral offset. The results show that the divergent emission profile of blue micro-LEDs introduces tolerance to gap distance and lateral offset, thereby reducing the requirement of alignment accuracy. Moreover, a larger fiber core diameter can leverage such emission profile and thus improves coupling efficiency. Strategies are proposed to further maximize coupling efficiency, including the employment of interface filling and micro-lenses. The findings provide comprehensive insights and practical guidelines for advancing the performance of micro-LED-based optical optical communication systems.