US Patent 11314018 Polymer optical waveguide and composite optical waveguide

The present invention relates to a polymer optical waveguide including: a core; an under-cladding; and an over-cladding, in which the polymer optical waveguide includes a coupling section and an optical waveguide section that are provided along a light propagation direction, the polymer optical waveguide includes portions having different core widths along the light propagation direction, and when a core width at a portion a having a narrowest core width is denoted Wa (μm) and a core height at the portion a is denoted Ha (μm), Ha is 1.3 μm or more and 4.5 μm or less, and Ha/Wa is 1.15 or less.