Self-written waveguide (SWW) optical pin for high optical coupling in multi-layer printed wiring board

Abstract

The future of optical interconnection needs for high optical coupling efficiency for high density multi-layer printed wiring board (PWB). Hence, a self-written waveguide (SWW) optical pin is implemented between surface device and multi-layer channel as optical coupling for reaching high coupling efficiency. A comparatively studies of three configurations of coupling methods was carried out by ray-tracing simulation. The correlation between optical coupling efficiency and mirror angle was analyzed as well as the relationship between optical coupling efficiency and photodiode (PD) positional. A maximum value of optical coupling efficiency with optical pin is obtained for both correlations. The 1 dB down-tolerance width of the correlation between optical coupling efficiency and the mirror angle for vertical pin (case 1) is larger compared to case 2 and case 3 (without vertical pin). For the relationship between optical coupling efficiency and PD positional error, the 1 dB down-tolerance widths for case 1, case 2 and case 3 were ±13μm, ±19μm and ±20μm, respectively. From this result, it is found that vertical pin is well-suited to satisfy both coupling efficiency and tolerance for shifting mirror angle and PD positional error.