RT Journal Article
T1 Parabolic dielectric reflector for extreme on-chip spot-size conversion with broad bandwidth.
A1 Moreno-Pozas, Laureano
A1 Barona-Ruiz, Miguel
A1 Halir, Robert
A1 De-Oliva-Rubio, José
A1 Rivas-Fernández, Jorge
A1 Molina-Fernández, Íñigo
A1 Wanguemert-Pérez, Juan Gonzalo
A1 Ortega-Moñux, Alejandro
K1 Fotónica
K1 Convertidores de frecuencia
K1 Difracción
AB Spot-size converters (SSCs) are key for efficient coupling of light between waveguides of different sizes. While adiabatic tapers are well suited for small size differences, they become impractically long for expansion factors around ×100, which are often required when coupling integrated waveguides and free-space beams. Evanescent couplers and Bragg deflectors can be used in this scenario, but their operation is inherently limited in bandwidth. Here, we propose a solution based on a parabolic dielectric interface that couples light from a 0.5um wide waveguide to a 285 um wide waveguide, i.e., an expansion factor of ×570. We experimentally demonstrate an unprecedented bandwidth of more than  380 nm with insertion losses below  0.35 dB. We furthermore provide analytical expressions for the design of such parabolic spot-size converters for arbitrary expansion factors.
PB Optica
YR 2025
FD 2025-02
LK https://hdl.handle.net/10630/40319
UL https://hdl.handle.net/10630/40319
LA eng
NO Moreno-Pozas, L., Barona-Ruiz, M., Halir, R., de-Oliva-Rubio, J., Rivas-Fernández, J., Molina-Fernández, I., ... & Ortega-Moñux, A. (2025). Parabolic dielectric reflector for extreme on-chip spot-size conversion with broad bandwidth. Optics Letters, 50(4), 1073-1076.
NO https://openpolicyfinder.jisc.ac.uk/id/publication/13362
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 24 ene 2026