@misc{SchenkVillasmuntaSteglichetal., author = {Schenk, Harald and Villasmunta, Francesco and Steglich, Patrick and Schrader, Sigurd and Mai, Andreas}, title = {Numerical Simulation of Optical Through-Silicon Waveguide for 3D Photonic Interconnections}, series = {2021 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD)}, journal = {2021 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD)}, publisher = {IEEE}, isbn = {978-1-6654-1276-6}, issn = {2158-3242}, doi = {10.1109/NUSOD52207.2021.9541464}, pages = {2}, abstract = {Optical interconnections are a promising step for-ward to overcome the intrinsic limitations of electrical inter-connections in integrated circuits. In this work, we present a finite element method (FEM) simulation study of a dielectric waveguide etched through the full thickness of a silicon substrate. In particular, it is investigated the effect of the bridge-to-core size ratio on the first two supported modes. Then, the influence of the waveguide sidewalls tapering angle on the three-dimensional beam propagation is studied. Such optical through-silicon waveguide (OTSW), if nonadiabatically tapered can provide effective mode size conversion and favour the coupling of external light sources to photonic integrated circuits.}, language = {en} } @misc{VillasmuntaSteglichHeinrichetal., author = {Villasmunta, Francesco and Steglich, Patrick and Heinrich, Friedhelm and Villringer, Claus and Mai, Andreas and Schrader, Sigurd and Schenk, Harald}, title = {Optical Through-Silicon Waveguides for 3D-Chip-Interconnections}, abstract = {Integrated optical interconnections in silicon chips have the potential to replace electrical interconnects between integrated circuits thanks to their high bandwidth and low energy communication promises. A silicon dielectric waveguide can be etched through the full thickness of a silicon substrate providing a monolithically integrated solution for 2.5D and 3D photonic architectures. The optical through-silicon waveguide design presented here is based on Finite Difference Time Domain simulations, while the fabrication takes advantage of the innovative plasma cryo-etching process that provides smooth sidewalls and tapering angle tunability. Such structures can provide effective mode size conversion, therefore favoring the coupling of external light sources to photonic integrated circuits and the stacking of multiple optically interconnected dies.}, language = {en} } @misc{VillasmuntaSteglichVillringeretal., author = {Villasmunta, Francesco and Steglich, Patrick and Villringer, Claus and Schrader, Sigurd and Schenk, Harald and Mai, Andreas and Regehly, Martin}, title = {Design, fabrication, and characterization of integrated optical through-silicon waveguides for 3D photonic interconnections}, series = {Optical Interconnects XXIV}, journal = {Optical Interconnects XXIV}, editor = {Schr{\"o}der, Henning and Chen, Ray T.}, publisher = {SPIE}, doi = {10.1117/12.3003146}, pages = {12}, language = {en} } @misc{VillasmuntaHeiseBreiteretal., author = {Villasmunta, Francesco and Heise, Patrick and Breiter, Manuela and Schrader, Sigurd and Schenk, Harald and Regehly, Martin and Mai, Andreas}, title = {Monolithically integrated optical through-silicon waveguides for 3D chip-to-chip photonic interconnects}, series = {IEEE journal of selected topics in quantum electronics}, volume = {32}, journal = {IEEE journal of selected topics in quantum electronics}, number = {2: 3-D Horizons in Photonics}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {New York, NY}, issn = {1077-260X}, doi = {10.1109/JSTQE.2025.3615001}, pages = {1 -- 15}, abstract = {The scaling limitations of electrical interconnects are driving the demand for efficient optical chip-to-chip links. We report the first monolithic integration of air-clad optical through-silicon waveguides in silicon, fabricated via Bosch and cryogenic deep reactive-ion etching. Rib, single-bridge, and double-bridge designs with 50 μm cores and up to 150 μm propagation lengths have been evaluated. Cryogenic-etched rib waveguides achieve the highest median transmission (66\%, -1.80 dB), compared to Bosch-etched ribs (62\%, -2.08 dB). Across all geometries, 3 dB alignment windows range from 9.3 μm to 49.2 μm, with Bosch-etched double-bridge waveguides providing the broadest tolerance. We show that geometric fidelity outweighs sidewall roughness for transmission and alignment in these large-core, multimode optical through-silicon waveguides. This technology provides a scalable, complementary metal-oxide semiconductor-compatible pathway toward 3D photonic interconnects.}, language = {en} }