Planar waveguide to vertical mode couplers covering the visible to IR spectral range

Opt Express. 2024 Oct 21;32(22):38128-38135. doi: 10.1364/OE.539044.

Abstract

Planar 45o turning mirrors with metal coating embedded in SU8 polymer waveguides enable waveguide to vertical mode coupling across a broad range of wavelengths from the visible to IR. The fabrication of these 2.5D structures is achieved using relatively simple grayscale lithography in thin film resists, compatible with standard planar lithography methods. Mirror losses of <1 dB are measured from 516 -1630 nm, and direct coupling to single mode fibre is achieved.