RT Journal Article
T1 Ultra-efficient surface grating couplers for chip-to-fiber and chip-to-free-space coupling based on single-beam radiation.
A1 Sánchez-Postigo, Alejandro
A1 Ginel-Moreno, Pablo
A1 Schmid, Jens H.
A1 Hadij-El-Houati, Abdelfettah
A1 Ortega-Moñux, Alejandro
A1 Wanguemert-Pérez, Juan Gonzalo
A1 Halir, Robert
A1 Cheben, Pavel
A1 Molina-Fernández, Íñigo
K1 Circuitos integrados
K1 Óptica integrada
AB Surface grating couplers, such as fiber-chip grating couplers and optical antennas, are fundamental devices in photonic integrated circuits, as they enable the coupling of light between the chip and an external medium. An important metric of surface grating couplers is the coupling efficiency, and high values, greater than -1 dB, are required for applications in quantum technology, light detection and ranging, and optical interconnects. Surface grating couplers typically suffer from radiation loss to the substrate, which significantly limits their coupling efficiency. Here we propose a novel grating-coupling concept that utilizes a high-refractive-index upper cladding to frustrate radiation orders to the substrate by operating in a single-beam diffraction regime. To illustrate this concept, we report the design of an easily fabricable silicon surface grating coupler with an unprecedented coupling efficiency of -0.2 dB to a single-mode optical fiber. Furthermore, the proposed strategy allows us to design an evanescently coupled millimeter-long optical antenna with a coupling efficiency of -0.1 dB to free space. Additionally, an ultra-fast wavelength-tunable beam steering of 0.37°/nm is achieved, which corresponds to more than a 2.5-fold enhancement over comparable silicon antennas. These results represent a pathway for a new set of photonic integrated interfaces for applications in which high-efficiency chip-to-fiber and chip-to-free-space coupling is critical.
PB Optica Publishing Group
YR 2024
FD 2024-10-28
LK https://hdl.handle.net/10630/35014
UL https://hdl.handle.net/10630/35014
LA eng
NO National Research Council Canada (HTSN 209, STR2-0102); Ministerio de Ciencia, Innovación y Universidades (PDC2023-145833-I00, TED2021-130400B-I00/ AEI/10.13039/501100011033/ Unión Europea NextGeneration EU/PRTR, PID2023-151178OB-I00); Universidad de Málaga
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 5 mar 2026