Low-cost micro-optics for PCB-level photonic interconnects

One of the grand challenges in solving the interconnection bottlenecks at the Printed Circuit Board (PCB) and Multi-Chip-Module (MCM) level, is to adequately replace the PCB and intra-MCM galvanic interconnects with high-performance, low-cost, compact and reliable micro-photonic-alternatives. Therefore we address the following components in this paper: 1) out-of-plane couplers for optical waveguides embedded in PCB, 2) peripheral fiber ribbons and two-dimensional single- and multimode fiber connectors for high-speed parallel optical connections, and 3) intra-MCM level optical interconnections via free-space optical modules. For the fabrication of these micro-optical interconnect modules, we are focusing at the Vrije Universiteit Brussel on the continuous development of a rapid prototyping technology, which we call Deep Proton Writing (DPW). The special feature of this prototyping technology is that it is compatible with commercial low-cost mass replication techniques such as micro injection moulding and hot embossing. Laser ablation is used at Ghent University for the fabrication of PCB-embedded waveguides; and integrated micro-mirrors. The main advantage of this technology is that it is compatible with present-day PCB manufacturing. For the free-space MCM-level optical interconnect module, we furthermore give special attention to the optical tolerancing and the opto-mechanical integration of the components. We use both a sensitivity analysis to misalignment errors and Monte Carlo simulations. It is our aim to investigate the whole component integration chain from the optoelectronic device to the micro-opto-mechanical components constituting the interconnect module.