Research Topics

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Low-loss Nanophotonic waveguides

Research Area: Silicon Photonics Process Technology

Main Researcher: Wim Bogaerts

One of the major issues in Nanophotonics and Photonic Crystal research is the quest for a low-loss waveguide. Photonic crystal waveguides perform poorly with respect to losses compared to conventional 'broad' waveguides. The major culprits for the high losses of photonic crystal waveguides are

Incoupling loss
Losses at irregularities due to fabrication
Out-of-plane scattering

Photonic wires are an alternative to photonic crystals. Wires are scaled-down ridge waveguides with a high idex contrast, and therefore high confinement that allows for sharp bends. Like photonic crystals, wires also suffer from scattering loss at roughness.

Out-of-plane scattering losses in photonic crystals

We made an extensive study of out-of-plane scattering losss in photonic crystals. Our conclusions are that for low index contrast, each hole in the photonic crystal couples light to the radiation modes. However, defects in the waveguides behave similar to the regular crystal. For high index contrast light can be guided in a lossless Guided Bloch mode. However, a defect that disrupts the periodicityis likely to cause huge scattering.

Scattering at sidewall roughness

Another problem is the scattering at sidewall roughness, mainly caused by dry etching. We again compared waveguides with high and low vertical index contrast, and found that the losses increases with lower index contrast. This might explain why SOI photonic crystals and membranes still perform better that their III-V counterparts.

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Experimental results

We have characterised photonic crystal waveguides and photonic wires fabricated with deep UV lithography in Silicon-on-insulator. Deeply etched waveguides have high losses (20dB/mm for a PhC, 30dB/mm for a 500nm wire). With only a Silicon etch, roughness decreases dramatically, and losses drop to 2.4dB/cm for 500nm wires and 7.5dB/mm for W1 photonic crystal waveguides.

Other people involved:

Related Research Projects

IST: PICCO (Photonic Integrated Circuits using photonic Crystal Optics)
IAP-V: PHOTON (Photons and Photonics : from basic physics to system concepts)
IST: ePIXnet (European Network of Excellence on Photonic Integrated Components and Circuits)
NEDO: PhotoCryst (Topographic Optimization of photonic crystals and application to ultrasmall and ultra-fast optical signal processing devices)
ICT: HELIOS (pHotonics ELectronics functional Integration on CMOS)
ICT: SOFI (Silicon-Organic hybrid Fabrication platform for Integrated circuits)

Downloads
(Nano)photonics in Silicon(-on-Insulator)

PhD thesises
Wim Bogaerts, Nanofotonische Golfgeleiders en Fotonische Kristallen in Silicium-op-Isolator, Nanophotonic Waveguides and Photonic Crystals in Silicon-on-Insulator, (4/2004)
Pieter Dumon, Ultra-compacte geïntegreerde optische filters in silicium-op-isolator op basis van waferschaaltechnologie, Ultra-Compact Integrated Optical Filters in Silicon-on-insulator by Means of Wafer-Scale Technology, (3/2007)
Publications
International Journals

M. Muneeb, X. Chen, P. Verheyen, G. Lepage, S. Pathak, E.M.P. Ryckeboer, A. Malik, B. Kuyken, M. Nedeljkovic, J. Van Campenhout, G. Mashanovich, G. Roelkens, Demonstration of silicon on insulator mid-infrared spectrometers operating at 3.8um, Optics Express, 21(10), p.11659-11669 doi:10.1364/OE.21.011659 (2013)  .
P. De Heyn, D. Vermeulen, D. Van Thourhout, G. Roelkens, Silicon-on-insulator all-pass microring resonator using a polarization rotating coupling section, IEEE Photonics Technology Letters, doi:10.1109/lpt.2012.2198460 (2012)  .
W. Bogaerts, S. Selvaraja, P. Dumon, J. Brouckaert, K. De Vos, D. Van Thourhout, R. Baets, Silicon-on-Insulator Spectral Filters Fabricated with CMOS Technology, J. Sel. Top. Quantum Electron. (invited), 16(1), p.33-44 doi:10.1109/JSTQE.2009.2039680 (2010)  .
D. Neel, T. Benyattou, P. Sanchis, J. Marti, W. Bogaerts, P. Dumon, R. Baets, Optical near-field study of photonic crystal tapers, Applied Optics, 48(30), p.5718-5721 doi:10.1364/AO.48.005718 (2009)  .
S. Clemmen, K. Phan Huy, W. Bogaerts, R. Baets, Ph. Emplit, S. Massar, Continuous wave photon pair generation in silicon-on-insulator waveguides and ring resonators, Optics Express, 17(19), p.16558-16570 doi:10.1364/OE.17.016558 (2009)  .
A. Kazmierczak, W. Bogaerts, E. Drouard, F. Dortu, P. Rojo-Romeo, F. Gaffiot, D. Van Thourhout, D. Giannone, Highly Integrated Optical 4x4 Crossbar in Silicon-on-Insulator Technology, Journal of Lightwave Technology, 27(16), p.3317-3323 doi:10.1109/JLT.2008.2010462 (2009)  .
J. Schrauwen, D. Van Thourhout, R. Baets, Trimming of silicon ring resonator by electron beam induced compaction and strain, Optics Express, 16(6), p.3738-3743 doi:10.1364/oe.16.003738 (2008)  .
W. Bogaerts, P. Dumon, D. Van Thourhout, R. Baets, Low-Loss, Low-Crosstalk Crossings for SOI Nanophotonic Waveguides, Optics Letters, 32(19), p.2801-2803 doi:10.1364/OL.32.002801 (2007)  .
W. Bogaerts, D. Taillaert, P. Dumon, D. Van Thourhout, R. Baets, A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonic wires, Optics Express, 15(4), p.1567-1578 doi:10.1364/oe.15.001567 (2007)  .
W. Bogaerts, P. Dumon, D. Van Thourhout, D. Taillaert, P. Jaenen, J. Wouters, S. Beckx, R. Baets, Compact Wavelength-Selective Functions in Silicon-on-Insulator Photonic Wires, J. Selected Topics in Quantum Electronics, 12(6), p.1394-1401 doi:10.1109/jstqe.2006.884088 (2006)  .
W. Bogaerts, R. Baets, P. Dumon, V. Wiaux, S. Beckx, D. Taillaert, B. Luyssaert, J. Van Campenhout, P. Bienstman, D. Van Thourhout, Nanophotonic Waveguides in Silicon-on-Insulator Fabricated with CMOS Technology, Journal of Lightwave Technology (invited), 23(1), p.401-412 doi:10.1109/JLT.2004.834471 (2005)  .
W. Bogaerts, P. Dumon, D. Taillaert, V. Wiaux, S. Beckx, B. Luyssaert, J. Van Campenhout, D. Van Thourhout, R. Baets, SOI Nanophotonic Waveguide Structures Fabricated with Deep UV Lithography , Photonics and Nanostructures: Fundamentals and Applications (invited), 2(2), p.81-86 doi:10.1016/j.photonics.2004.07.002 (2004)  .
P. Dumon, W. Bogaerts, V. Wiaux, J. Wouters, S. Beckx, J. Van Campenhout, D. Taillaert, B. Luyssaert, P. Bienstman, D. Van Thourhout, R. Baets, Low-loss SOI Photonic Wires and Ring Resonators Fabricated with Deep UV Lithography, IEEE Photonics Technology Letters, 16(5), p.1328-1330 doi:10.1109/lpt.2004.826025 (2004)  .
W. Bogaerts, D. Taillaert, B. Luyssaert, P. Dumon, J. Van Campenhout, P. Bienstman, D. Van Thourhout, R. Baets, V. Wiaux, S. Beckx, Basic structures for photonic integrated circuits in Silicon-on-insulator, Optics Express (invited), 12(8), p.1583-1591 doi:10.1364/OPEX.12.001583 (2004)  .
W. Bogaerts, P. Bienstman, R. Baets, Scattering at sidewall roughness in photonic crystal slabs, Optics Letters, 28(9), p.689-691 doi:10.1364/OL.28.000689 (2003)  .

International Conferences

R. Baets, A. Subramanian, A. Dhakal, S. Selvaraja, K. Komorowska, F. Peyskens, E.M.P. Ryckeboer, N.A Yebo, G. Roelkens, N. Le Thomas, Spectroscopy-on-chip applications of silicon photonics, Photonics West (invited), 8627(01), United States, p.86270I-1 - 86270I-10 doi:10.1117/12.2010498 (2013)  .
G. Murdoch, A. Milenin, C. Delveauz, P. Ong, S. Pathak, D. Vermeulen, G. Sterckx, G. Winroth, P. Verheyen, G. Lepage, W. Bogaerts, R. Baets, J. Van Campenhout, P. Absil, Advanced 300-mm waferscale patterning for silicon photonics devices with record low loss and phase errors, the 17th OpeoElectronics and Communications Conference, South Korea, p.15-16 (2012)  .
P. De Heyn, D. Vermeulen, T. Van Vaerenbergh, B. Kuyken, D. Van Thourhout, Ultra-high Q and finesse all-pass microring resonators on Silicon-on-Insulator using rib waveguides, 16th European Conference on Integrated Optics and technical exhibition, Spain, p.paper 195 (2012)  .
W. Bogaerts, S. Selvaraja, H. Yu, T. Spuesens, P. Mechet, S. Stankovic, S. Keyvaninia, J. Van Campenhout, P. Absil, G. Roelkens, D. Van Thourhout, R. Baets, A Silicon Photonics Platform with Heterogeneous III-V Integration, Integrated Photonics Research, Silicon and Nano-Photonics (IPR) (invited), Canada, p.IWC2 doi:10.1364/iprsn.2011.iwc2 (2011)  .
W. Bogaerts, P. Absil, D. Van Thourhout, J. Van Campenhout, S. Selvaraja, P. Dumon, H. Yu, A. Masood, G. Roelkens, R. Baets, Optical Interconnect Technologies based on Silicon Photonics, MRS Spring 2011 (invited), United States, p.O10.1 (2011)  .
P. De Heyn, B. Kuyken, D. Vermeulen, W. Bogaerts, D. Van Thourhout, High-performance low-loss silicon-on-insulator microring resonators using TM-polarized light, The Optical Fiber Communication Conference and Exposition (OFC) and The National Fiber Optic Engineers Conference (NFOEC) 2011, , United States, p.paper OThV2 (3 pages) doi:10.1364/ofc.2011.othv2 (2011)  .
P. De Heyn, B. Kuyken, D. Vermeulen, W. Bogaerts, D. Van Thourhout, Improved intrinsic Q of Silicon-on-Insulator microring resonators using TM-polarized light, Proceedings of the 2010 Annual Symposium of the IEEE Photonics Benelux Chapter, Netherlands, p.197-200 (2010)  .
W. Bogaerts, P. Dumon, S. Selvaraja, D. Van Thourhout, R. Baets, Silicon nanophotonic waveguide components, Silicon Nanoelectronics and Photonics (SiNEP) 2009 (invited), Spain, p.33-34 (2009)  .
J. Teng, P. Dumon, W. Bogaerts, H. Zhang, X. Jian, M. Zhao, G. Morthier, R. Baets, Athermal SOI ring resonators by overlaying a polymer cladding on narrowed waveguides, 6th IEEE International Conference on Group IV Photonics, United States, p.ThB2 doi:10.1109/group4.2009.5338355 (2009)  .
S. Selvaraja, P. Jaenen, S. Beckx, W. Bogaerts, P. Dumon, D. Van Thourhout, R. Baets, Silicon nanophotonic wire structures fabricated by 193nm optical lithography , LEOS Annual Meeting 2007 (invited), United States, doi:10.1109/leos.2007.4382268 (2007)  .
W. Bogaerts, P. Dumon, J.-M. Fedeli, A. Tchelnokov, D. Van Thourhout, S. Selvaraja, R. Baets, A Platform for Silicon-on-Insulator Nanophotonics on Industrial CMOS Tools, Photonic and Electromagnetic Crystal Structures (PCS-VII), United States, (2007)  .
R. Baets, W. Bogaerts, D. Taillaert, P. Dumon, D. Van Thourhout, SOI Photonic Wire Based Components with Compact and Efficient Fiber Couplers , Optical Fiber Communications (invited), United States, p.OWG3 doi:10.1109/ofc.2007.4348871 (2007)  .
W. Bogaerts, P. Dumon, D. Van Thourhout, R. Baets, Compact, Low-Loss Waveguide Crossings for High-Index-Contrast SOI Photonic Wires , Optical Fiber Communications, United States, p.OTuM1 doi:10.1109/ofc.2007.4348825 (2007)  .
W. Bogaerts, D. Taillaert, P. Dumon, E. Pluk, D. Van Thourhout, R. Baets, A Compact Polarization-Independent Wavelength Duplexer Using a Polarization-Diversity SOI Photonic Wire Circuit , Optical Fiber Communications, United States, p.OTuM2 doi:10.1109/ofc.2007.4348826 (2007)  .
W. Bogaerts, P. Dumon, J. Wouters, P. Jaenen, S. Beckx, V. Wiaux, D. Van Thourhout, D. Taillaert, B. Luyssaert, R. Baets, Silicon-on-Insulator Nanophotonics, SPIE Optics and Optoelectronics (invited), 5956, Poland, p.5956R-1-15 (2005)  .
R. Baets, D. Van Thourhout, G. Morthier, W. Bogaerts, L. Vanholme, Silicon-on-insulator based high index contrast waveguide devices: research in europe, 11th Microoptics Conference (MOC) (invited), Japan, p.E2, Session C ( 4 pages) (2005)  .
P. Dumon, G. Roelkens, W. Bogaerts, D. Van Thourhout, J. Wouters, S. Beckx, P. Jaenen, R. Baets, Basic Photonic Wire Components in Silicon-on-Insulator, Group IV Photonics, Belgium, p.189-191 doi:10.1109/group4.2005.1516448 (2005)  .
P. Dumon, R. Baets, R. Kappeler, D. Barros, I. McKenzie, D. Doyle, Measured radiation sensitivity of Silica-on-Silicon and Silicon-on-insulator micro-photonic devices for potential space application, Optics and Photonics, Photonics for Space Environments X, 5897, United States, doi:10.1117/12.617024 (2005)  .
D. Taillaert, R. Baets, P. Dumon, W. Bogaerts, D. Van Thourhout, B. Luyssaert, V. Wiaux, S. Beckx, J. Wouters, Silicon-on-Insulator Platform for Integrated Wavelength-Selective Components, Workshop on Fibres and Optical Passive Components (invited), Italy, doi:10.1109/wfopc.2005.1462110 (2005)  .
D. Néel, T. Benyattou, R. Orobtchouk, P. Dumon, D. Van Thourhout, SNOM for the optical characterisation of photonic crystal structures, Workshop on Photonic and Electromagnetic Crystal Structures (PECS-VI), Greece, p.C.32 (2005)  .
D. Néel, T. Benyattou, R. Orobtchouk, P. Dumon, D. Van Thourhout, Near-field characterization of SOI photonic crystal structures, Internation Conference on Electromagnetic Near-Field Characterization & Imaging (ICONIC), Spain, (2005)  .
D. Neel, T. Benyattou, R. Orobtchouk, P. Dumon, D. Van Thourhout, L. El Melhaoui, J-M. Fedeli, Scanning Near-field Optical Microscopy for the study of photonic crystals optical components, 3rd Optoelectronic & Photonic Winter School, Italy, (2005).
P. Dumon, W. Bogaerts, D. Van Thourhout, D. Taillaert, V. Wiaux, S. Beckx, J. Wouters, R. Baets, Wavelength-selective components in SOI photonic wires fabricated with deep UV lithography, Group IV Photonics, Hong Kong, p.WB5 doi:10.1109/group4.2004.1416642 (2004)  .
P. Dumon, W. Bogaerts, D. Van Thourhout, D. Taillaert, V. Wiaux, S. Beckx, J. Wouters, R. Baets, Cascaded Mach-Zehnder Filters in Silicon-on-Insulator Photonic Wires fabricated with deep UV lithography, European Conference on Optical Communication (ECOC) 2004, Th.(Post-deadline), Sweden, p.24-25 (2004)  .
R. Baets, W. Bogaerts, Nanophotonic waveguides in SOI by means of deep UV lithography, Photonic and Electromagnetic Crystal Structures (PECS-V) (invited), Japan, p.160 (2004)  .
P. Dumon, W. Bogaerts, J. Van Campenhout, V. Wiaux, J. Wouters, S. Beckx, R. Baets, Low-loss photonic wires and compact ring resonators in silicon-on-insulator, LEOS Benelux Annual Symposium 2003, Netherlands, (2003)  .
W. Bogaerts, P. Dumon, V. Wiaux, J. Wouters, S. Beckx, R. Baets, Tolerance control for photonic crystal structures fabricated with deep UV lithography, ECOC 2003, 5, Italy, p.46-47 (2003)  .
W. Bogaerts, V. Wiaux, P. Dumon, D. Taillaert, J. Wouters, S. Beckx, J. Van Campenhout, B. Luyssaert, D. Van Thourhout, R. Baets, Large-scale production techniques for photonic nanostructures, Proc. SPIE (invited), 5225, United States, p.101-112 doi:10.1117/12.503665 (2003)  .
W. Bogaerts, P. Bienstman, R. Baets, Sidewall Roughness in Photonic Crystal Slabs: A Comparison of High-Contrast Membranes and Low-Contrast III-V Epitaxial Structures, European Conference on Integrated Optics (ECIO), Czech Republic, p.349-352 (2003)  .
T.F. Krauss, R. Wilson, R. Baets, W. Bogaerts, M. Kristensen, P.I. Borel, L.H. Frandsen, M. Thorhauge, B. Tromborg, A. Lavrinenko, R.M. De La Rue, H. Chong, L. Socci, M. Midrio, D. Gallagher, Photonic Integrated Circuits using Crystal Optics (PICCO), European Conference on Integrated Optics (ECIO) (invited), Czech Republic, p.113-117 (2003)  .
National Conferences

W. Bogaerts, P. Dumon, V. Wiaux, J. Wouters, S. Beckx, D. Taillaert, B. Luyssaert, J. Van Campenhout, D. Van Thourhout, R. Baets, Nanophotonic waveguides in Silicon-on-Insulator Fabricated with CMOS Technology, 4th UGent FTW PhD Symposium, Belgium, p.56 (2003)  .
J. Van Campenhout, W. Bogaerts, D. Taillaert, R. Baets, Compact photonic-crystal waveguides in Silicon-on-Insulator: design and experimental verification, LEOS Benelux Photonic Crystal Workshop, Belgium, (2002).
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