Optical interconnects replace electrical links increasingly at shorter distances. At printed circuit board (PCB) level highly multimodal polymer channel waveguides are the chosen approach to meet bandwidth-length and bandwidth-density requirements. One important challenge of board integrated waveguides is the coupling problem. The manufacturing process of PCBs leads to relatively high placement tolerances which cause poor optical coupling efficiency due to mechanical misalignment between separate components, e.g.: 1) Coupling between a VCSEL and the board integrated waveguides; 2) Coupling between waveguides in two separate boards. This paper deals with the deployment of tapered dielectric multimode waveguides for increasing the optical coupling robustness towards mechanical misalignments in these two coupling applications. A coupled mode approach for calculation of the mode coupling and power loss in a taper with decreasing width has been presented before [5]. In [6], the two above mentioned coupling applications for tapered dielectric waveguides have been dealt with, but only the coupling efficiency in case of longitudinal misalignment has been calculated. In this paper, results of advanced analysis of the two applications are presented. The coupling efficiency in case of transverse misalignment is simulated by a ray-optical approach. Furthermore the results of measurements of the coupling behaviour of board integrated tapered waveguides are presented. The results show that tapered multimodal dielectric waveguides have the capability to increase the coupling efficiency significantly if some conditions are fulfilled.

Date Published: 14 May 2010
PDF: 8 pages
Proc. SPIE 7716, Micro-Optics 2010, 77162F (14 May 2010); doi: 10.1117/12.854513

Published in SPIE Proceedings Vol. 7716:
Micro-Optics 2010
Hugo Thienpont; Peter Van Daele; Jürgen Mohr; Hans Zappe, Editor(s)