Polymer optical waveguide fabrication using laser ablation

Due to their inherent bandwidth capacity, optical interconnects are replacing copper as bottlenecks begin to appear within the various interconnect levels of electronic systems. Current optical interconnect solutions found in industry are based upon optical fibres and are capable of providing a suitable platform for inter-board applications. However, to allow high bit rate digital interconnects between components and within systems, optically enabled printed circuit boards containing waveguides are essential. One way in which this can be accomplished is through the integration of polymer optical waveguides into traditional printed circuit boards (PCBs). There are a number of routes to accomplish this including photolithography and laser direct imaging, however, this paper explores laser ablation using UV and IR sources namely: 248 nm Excimer, 355 nm UV Nd:YAG and 10.6 ¿m CO₂, to form waveguide structures in optical polymer materials. The paper presents the process route and initial results of trials conducted to fabricate waveguides and indicates the difference between the structures formed by the different lasers. The demonstration of the use of these three lasers for optical waveguide fabrication may provide a route to the rapid deployment of this technology into the PCB industry through the use of existing infrastructure.