Monolithically Integrated Optical Through-Silicon Waveguides for 3D Chip-to-Chip Photonic Interconnects
- 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.
| URN: | urn:nbn:de:kobv:526-opus4-20828 |
|---|---|
| Publisher DOI: | https://doi.org/10.1109/JSTQE.2025.3615001 |
| Author: | Francesco VillasmuntaORCiD, Patrick HeiseORCiD, Manuela Breiter, Sigurd SchraderORCiD, Harald Schenk, Martin RegehlyORCiDGND, Andreas MaiORCiD |
| Parent Title (English): | IEEE Journal of Selected Topics in Quantum Electronics |
| Document Type: | Article |
| Language: | English |
| Year of Publication: | 2026 |
| Volume: | 32 |
| Issue: | 2 |
| Article Number: | 3700215 |
| Publisher: | IEEE |
| Faculties an central facilities: | Fachbereich Ingenieur- und Naturwissenschaften |
| Year of first Publication: | 2025 |
| Publishing Institution: | Technische Hochschule Wildau |
| Tag: | coupler; coupling; optical coupling; optical device fabrication; optical interconnection; optical loss; optical surface wave; optical waveguide; silicon; silicon photonics; three-dimensional display; three-dimensional integrated circuit; through-silicon vias (TSV) |
| Source: | Villasmunta, F., Heise, P., Breiter, M., Schrader, S., Schenk, H., Regehly, M., & Mai, A. (2025). Monolithically Integrated Optical Through-Silicon Waveguides for 3D Chip-to-Chip Photonic Interconnects. IEEE Journal of Selected Topics in Quantum Electronics, 32(2), 3700215. doi:10.1109/JSTQE.2025.3615001 |
| Dewey Decimal Classification: | 6 Technik, Medizin, angewandte Wissenschaften / 62 Ingenieurwissenschaften / 621 Angewandte Physik |
| Licence (German): | Creative Commons - CC BY - Namensnennung 4.0 International |
| Release Date: | 2025/10/21 |



