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%Δ waveguide and a single mode fiber (SMF) was decreased to 0.06dB/facet, drastically.