OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 4 — Feb. 13, 2012
  • pp: 4331–4345

3-D integrated heterogeneous intra-chip free-space optical interconnect

Berkehan Ciftcioglu, Rebecca Berman, Shang Wang, Jianyun Hu, Ioannis Savidis, Manish Jain, Duncan Moore, Michael Huang, Eby G. Friedman, Gary Wicks, and Hui Wu  »View Author Affiliations

Optics Express, Vol. 20, Issue 4, pp. 4331-4345 (2012)

View Full Text Article

Enhanced HTML    Acrobat PDF (3639 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



This paper presents the first chip-scale demonstration of an intra-chip free-space optical interconnect (FSOI) we recently proposed. This interconnect system provides point-to-point free-space optical links between any two communication nodes, and hence constructs an all-to-all intra-chip communication fabric, which can be extended for inter-chip communications as well. Unlike electrical and other waveguide-based optical interconnects, FSOI exhibits low latency, high energy efficiency, and large bandwidth density, and hence can significantly improve the performance of future many-core chips. In this paper, we evaluate the performance of the proposed FSOI interconnect, and compare it to a waveguide-based optical interconnect with wavelength division multiplexing (WDM). It shows that the FSOI system can achieve significantly lower loss and higher energy efficiency than the WDM system, even with optimistic assumptions for the latter. A 1×1-cm2 chip prototype is fabricated on a germanium substrate with integrated photodetectors. Commercial 850-nm GaAs vertical-cavity-surface-emitting-lasers (VCSELs) and fabricated fused silica microlenses are 3-D integrated on top of the substrate. At 1.4-cm distance, the measured optical transmission loss is 5 dB, the crosstalk is less than −20 dB, and the electrical-to-electrical bandwidth is 3.3 GHz. The latter is mainly limited by the 5-GHz VCSEL.

© 2012 OSA

OCIS Codes
(130.3120) Integrated optics : Integrated optics devices
(220.0220) Optical design and fabrication : Optical design and fabrication
(250.5300) Optoelectronics : Photonic integrated circuits
(200.2605) Optics in computing : Free-space optical communication

ToC Category:
Integrated Optics

Original Manuscript: December 8, 2011
Revised Manuscript: January 29, 2012
Manuscript Accepted: January 30, 2012
Published: February 7, 2012

Berkehan Ciftcioglu, Rebecca Berman, Shang Wang, Jianyun Hu, Ioannis Savidis, Manish Jain, Duncan Moore, Michael Huang, Eby G. Friedman, Gary Wicks, and Hui Wu, "3-D integrated heterogeneous intra-chip free-space optical interconnect," Opt. Express 20, 4331-4345 (2012)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. J. W. Goodman, F. J. Leonberger, S. -Y. Kung, and R. A. Athale, “Optical interconnections for VLSI systems,” Proc. IEEE72(7), 850–866 (1984).
  2. D. A. B. Miller, “Optical interconnects to silicon,” IEEE J. Sel. Top. Quantum Electron.6(6), 1312–1317 (2000).
  3. L. Schares, J. A. Kash, F. E. Doany, C. L. Schow, C. Schuster, D. M. Kuchta, P. K. Pepeljugoski, J. M. Trewhella, C. W. Baks, R. A. John, L. Shan, Y. H. Kwark, R. A. Budd, P. Chiniwalla, F. R. Libsch, J. Rosner, C. K. Tsang, C. S. Patel, J. D. Schaub, R. Dangel, F. Horst, B. J. Offrein, D. Kucharski, D. Guckenberger, S. Hegde, H. Nyikal, C. -K. Lin, A. Tandon, G. R. Trott, M. Nystrom, D. P. Bour, M. R. T. Tan, D. W. Dolfi, and IBM T.J. Watson Research Center, “Terabus: terabit/second-class card-level optical interconnect technologies,” IEEE J. Sel. Top. Quantum Electron.12(5), 1032–1044 (2006).
  4. I. Young, E. Mohammed, J. Liao, A. Kern, S. Palermo, B. Block, M. Reshotko, and P. Chang, “Optical I/O technology for tera-scale computing,” IEEE Int. Solid-State Circuits Conf.468–469 (2009).
  5. R. G. Beausoleil, J. Ahn, N. Binkert, A. Davis, D. Fattal, M. Fiorentino, N. P. Jouppi, M. McLaren, C. M. Santori, R. S. Schreiber, S. M. Spillane, D. Vantrease, Q. Xu, and HP Labs, Palo Alto, CA, “A nanophotonic interconnect for high-performance many-core computation,” 16th IEEE Symp. High Performance Interconnects, HOTI ’08 182–189 (2008).
  6. D. V. Plant, M. B. Venditti, E. Laprise, J. Faucher, K. Razavi, M. Chteauneuf, A. G. Kirk, and J. S. Ahearn, “256-channel bidirectional optical interconnect using VCSELs and photodiodes on CMOS,” IEEE J. Ligthwave Technol.19(8), 1093–1103 (2001).
  7. J. Jahns, “Planar packaging of free-space optical interconnections”, Proc. IEEE82(11), 769–779 (1994).
  8. M. W. Haney, M. P. Christensen, P. Milojkovic, G. J. Fokken, M. Vickberg, B. K. Gilbert, J. Rieve, J. Ekman, P. Chandramani, F. Kiamilev, and George Mason Univ., Fairfax, VA, “Description and evaluation of the FAST-Net smart pixel-based optical interconnection prototype,” Proc. IEEE88(6), 819–828 (2000).
  9. H. Thienpont, C. Debaes, V. Baukens, H. Ottevaere, P. Vynck, P. Tuteleers, G. Verschaffelt, B. Volckaerts, A. Hermanne, M. Hanney, and Vrije Univ., Brussels, “Plastic microoptical interconnection modules for parallel free-space inter- and intra-MCM data communication,” Proc. IEEE88(6), 769–779 (2000).
  10. C. Debaes, M. Vervaeke, V. Baukens, H. Ottevaere, P. Vynck, P. Tuteleers, B. Volckaerts, W. Meeus, M. Brunfaut, J. Van Campenhout, A. Hermanne, and H. Thienpont, “Low-cost microoptical modules for MCM level optical interconnections,” IEEE J. Sel. Top. Quantum Electron.9(2), 518–530 (2003).
  11. M. J. McFadden, M. Iqbal, T. Dillon, R. Nair, T. Gu, D. W. Prather, and M. W. Haney, “Multiscale free-space optics interconnects for intrachip global communication: motivation, analysis, and experimental validation,” Appl. Opt.45(25), 6358–6366 (2006). [PubMed]
  12. B. Ciftcioglu, R. Berman, J. Zhang, Z. Darling, S. Wang, J. Hu, J. Xue, A. Garg, M. Jain, I. Savidis, D. Moore, M. Huang, E. G. Friedman, G. Wicks, and Hui Wu, “A 3-D integrated intra-chip free-space optical interconnect for many-core chips,” IEEE Photon. Technol. Lett.23(3), 164–166 (2011).
  13. J. Xue, A. Garg, B. Ciftcioglu, Jianyun Hu, S. Wang, I. Savidis, M. Jain, R. Berman, P. Liu, M. Huang, H. Wu, E. Friedman, G. Wicks, and D. Moore, “An intra-chip free-space optical interconnect,” 37th Int. Symp. Computer Architecture ISCA 94–105 (2010).
  14. D. Louderback, O. Sjolund, E. R. Hegblom, S. Nakagawa, J. Ko, and L. A. Coldren, “Modulation and free-space link characteristics of monolithically integrated vertical-cavity lasers and photodetectors with microlenses,” IEEE J. Sel. Top. Quantum Electron.5(2), 155–165 (1999).
  15. Y. -C. Chang and L. A. Coldren, “Optimization of VCSEL structure for high-speed operation,” IEEE 21st Int. Semiconductor Laser Conf., ISLC 159–160 (2008).
  16. P. Dong, S. Liao, D. Feng, H. Liang, D. Zheng, R. Shafiiha, C. -C. Kung, W. Qian, G. Li, X. Zheng, A. V. Krishnamoorthy, and M. Asghari, “Low Vpp, ultralow-energy, compact, high-speed silicon electro-optic modulator,” Opt. Express17(25), 22484–22490 (2009).
  17. J. Cardenas, C. B. Poitras, J. T. Robinson, K. Preston, L. Chen, and M. Lipson, “Low loss etchless silicon photonic waveguides,” Opt. Express17(6), 4752–4757 (2009). [PubMed]
  18. “International Technology Roadmap of Semiconductors,” www.itrs.net . (2009).
  19. Q. Xu, S. Manipatruni, B. Schmidt, J. Shakya, and M. Lipson, “12.5 Gbit/s carrier-injection-based silicon microring silicon modulators,” Opt. Express15(2), 430–436 (2007). [PubMed]
  20. B. Ciftcioglu, J. Zhang, R. Sobolewski, and H. Wu, “An 850-nm normal-incidence germanium metal-semiconductor-metal photodetector with 13-GHz bandwidth and 8-μA dark current,” IEEE Photon. Technol. Lett.22(24), 1851–1853 (2010).
  21. F. T. O’Neill and J. T. Sheridan, “Photoresist reflow method of microlens production part I: background and experiments,” Optik113(9), 391–404 (2002).

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited