Board-Level Single-mode Polymer Optical Waveguides

In optical interconnects, there is an increasing discrepancy between current proposals for optical backplanes, which strongly focus on multimodal waveguides, and those for very high capacity transmitter and receiver modules being realized in silicon photonics, which focus on single mode transmission systems. In this paper we present a boardlevel single mode polymer optical waveguide technology which may merge these two worlds. First, the refractive indices of selected commercially available polymers have been measured, and used as an input for the design of the single-mode waveguides. Simulations are performed using an FDTD (finite-difference time domain) method (Lumerical). Depending on the core/cladding material combination, point-to-point square waveguide structures, with typical dimensions between 1x1 μm and 5x5 μm, have been fabricated by laser direct imaging (LDI).