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Summary Acknowledgments 2022).
This work details the packaging Co-authors of this article are: Robert 6. R. Marchetti, et al., “Coupling
approaches that are modified for different PIC Be r n son , Pa r n i k a G upt a , K a m il strategies for silicon photonics
and glass interposer coupling architectures Gradkowski (Tyndall National Institute, integrated chips,” Photon. Res. 7, 201-
based on their vertical integration University College Cork, Ireland), 239 (2019).
requirements. The two vertical integration Samuel Serna (Massachusetts Institute 7. S. Wakeel, et al., “Constituents and
schemes, 3D printed free-form couplers and of Technology and Bridgewater State performance of no-clean flux for
inverse tapers, for coupling light between PIC University), and Drew Weninger, Juejun Hu electronic solder,” Microelectronics
and glass interposer are required for allowing (Massachusetts Institute of Technology). Reliability 123 (2021): 114177.
high-density off-chip optical interconnects The authors acknowledge funding support 8. S. Wakeel, et al., “Effects of
and can enable these technologies to be provided by the MIT MISTI Global Seed commercial no-clean f lux on
used for wavelength division multiplexing Funds and the Irish Photonic Integration reliability of fine pitch flip-chip
in optical transceivers, broadband optical Center (IPIC). This article was presented at package with solder bumps and copper
sensing, etc. These packaging strategies are the 25th Electronics Packaging Technology pillars,” IEEE Trans. on Components,
scalable and geared towards using existing Conference (EPTC 2023) and was edited Packaging and Manufacturing
surface mounting processes such as solder for publication in Chip Scale Review. Technology 12.8 1386-1394 (2022).
reflow and optical epoxy bonding to optimize 9. H. Lu, et al., “Flip-chip integration of
the optical coupling between the photonic References tilted VCSELs onto a silicon photonic
chips and glass interposer. 1. D. Weninger, et al., “High density integrated circuit,” Opt. Express
Next steps include the development of vertical optical interconnects for 24.1516258-16266 (2016).
photonic packaging demonstrators based passive assembly,” Opt. Express 31, 10. L. V. Rodríguez-de Marcos, et al.,
on free-form couplers and inverse tapers. 2816-2832 (2023). “Self-consistent optical constants of
In addition, there are further experiments 2. L. Ranno, et al., “Integrated SiO 2 and Ta 2 O 5 films,” in Opt. Mater.
underway to test the mechanical reliability Photonics Packaging: Challenges and Express 6, 3622-3637 (2016).
of solder joints and epoxies when exposed to Opportunities,” ACS Photonics 9(11),
varying temperature conditions. 3467-3485 (2022)

Biographies
Saif Wakeel is a PhD student in the Photonic Packaging and Integration Group at Tyndall National
Institute, Cork City, Ireland, under the supervision of Prof. Peter O’Brien. Before joining Tyndall, he was a
packaging engineer with NXP Semiconductors in Malaysia. He was also a Research Intern at the National U.
of Singapore (NUS), Singapore. His research interests include wafer-level photonic and electronic packaging,
novel micro-optics and integration methods, micro-transfer printing, and the reliability of photonic packaging.
He has authored several publications, and two invited books with 380+ citations.

Prof. Peter O’Brien is head of the Photonics Packaging & Systems Integration Group at the Tyndall Institute, University
College Cork, Cork City, Ireland. He is Director of the European Photonics Pilot Line (www.pixapp.eu) and the new European
Photonics Academy at PhotonHub Europe (www.photonhub.eu). He previously founded and was CEO of a start-up company
manufacturing speciality photonic systems for biomedical applications, which he sold in 2009. He was a post-doctoral scholar
at the California Institute of Technology and a research scientist at NASA’s Jet Propulsion Laboratory. He received his
degree and PhD in Physics from Trinity College Dublin and U. College Cork, respectively. Contact author Peter O’Brien at
peter.obrien@tyndall.ie

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