arXiv subjects

Adrià Grabulosa

Publications and source records attributed to Adrià Grabulosa.

3 recordsLinked to original sources

arXiv2026

3D Photonic integration leveraging hybrid-confinement circuits

Three-dimensional (3D) photonic integration offers a pathway to overcome the fundamental scaling limitations of planar platforms by enabling enhanced routing flexibility for compact, low-loss, and highly interconnected photonic circuits. In this work, we fabricate 3D photonic circuits combining high-confinement air-clad waveguides for compact routing with low-confinement polymer-clad waveguides for robust single-mode operation within a monolithic platform. Efficient mode transition between polymer-clad and air-clad waveguides is demonstrated with a loss of 0.25 dB per interface. We also realize compact, Euler S- and U-shaped bends with minimal bending radii of 10 $μ$m and losses as low as 0.5 dB and 0.4 dB, respectively, along with compact adiabatic air-clad splitters exhibiting a splitting loss of 0.6~dB over a length of 52 $μ$m. Finally, full fabrication of a compact hybrid circuit is demonstrated, highlighting the feasibility and scalability of the approach. Our work represents a significant step in 3D photonic integration for applications including optical neural networks, photonic wire bonding and their potential for novel integrated photonic applications.

physics.optics↗

arXiv2024

Electrical Spectroscopy of Polaritonic Nanoresonators

One of the most captivating properties of polaritons is their capacity to confine light at the nanoscale. This confinement is even more extreme in two-dimensional (2D) materials. 2D polaritons have been investigated by optical measurements using an external photodetector. However, their effective spectrally resolved electrical detection via far-field excitation remains unexplored. This fact hinders their potential exploitation in crucial applications such as sensing molecules and gases, hyperspectral imaging and optical spectrometry, banking on their potential for integration with silicon technologies. Herein, we present the first electrical spectroscopy of polaritonic nanoresonators based on a high-quality 2D-material heterostructure, which serves at the same time as the photodetector and the polaritonic platform. We employ metallic nanorods to create hybrid nanoresonators within the hybrid plasmon-phonon polaritonic medium in the mid and long-wave infrared ranges. Subsequently, we electrically detect these resonators by near-field coupling to a graphene pn-junction. The nanoresonators simultaneously present a record of lateral confinement and high-quality factors of up to 200, exhibiting prominent peaks in the photocurrent spectrum, particularly at the underexplored lower reststrahlen band of hBN. We exploit the geometrical and gate tunability of these nanoresonators to investigate their impact on the photocurrent spectrum and the polaritonic's waveguided modes. This work opens a venue for studying this highly tunable and complex hybrid system, as well as for using it in compact platforms for sensing and photodetection applications.

physics.optics↗

arXiv2022

(3+1)D-printed adiabatic 1-to-N broadband couplers

We report single-mode 3D optical couplers leveraging adiabatic power transfer towards up to 4 output ports. We use the CMOS compatible additive (3+1)D \emph{flash}-TPP printing for fast and scalable fabrication. Coupling optical losses of such devices are reduced below $\sim$~0.06~dB by tailoring the coupling and waveguides geometry, and we demonstrate almost octave-spanning broadband functionality from 520~nm to 980~nm.

physics.optics↗