Vertical Spot Size Converter with 0.06dB/facet coupling loss using 2.5%Δ silica-based waveguide

A vertical spot size converter (SSC) with vertically tapered structure was made by using plasma enhanced chemical vapor deposition (PECVD) and a shadow mask. With the vertical SSC, a coupling loss between 2.5%Delta waveguide and a single mode fiber (SMF) was decreased to 0.06 dB/facet, drastically.