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Compact Circuit Models and Extraction

Research Area: Design and Modeling for Integrated Photonics, Large-scale Photonic Integration, Photonics-electronics convergence, Silicon Photonics Process Technology

Main Researcher: Ang Li

As Photonic integrated circuits become larger, the simulation of circuits becomes more important. But a circuit simulation is only as accurate as the models of the individual building blocks.

A good circuit model is fast, accurate and can capture the relevant physical effects. Such models can be implemented as mathematical expressions of the physical processes (white-box model) or as mathematical expressions that have no relation with the physics but mimic the correct response (black-box models).

We develop compact models based on both techniques for the elementary building blocks. Together with the models, we also develop the needed parameter extraction algorithms and test-suites, so the models can be populated based on actually fabricated devices.

Stochastic transmission model for waveguides
Stochastic transmission model for waveguides

A simple example of a device model that can be more complicated that originally conceived is that of the waveguide. The basic description of the waveguide is the effective index and the propagation loss. However, in a real waveguide the effective index is wavelength dependent. Extracting the effective index directly is far from straightforward. For this, we developed an extraction technique to measure the wavelength dependent effective index on a chip.

The propagation losses are equally complicated: in a real waveguide some light will be backreflected, and subsequenly recycled in a coherent way. This impacts the propagation loss, and the transmission becomes a stochastic process. Similar processes occur in directional couplers, grating couplers, ...

Effective index extraction  of a waveguide
Effective index extraction of a waveguide

Because backscattering in waveguides cause parasitic reflections, this can have an effect on larger circuit elements. For instance, in a ring resonator we see different origins of reflections, which contribute to a resonance splitting. By capturing those effects in a model, we can extract the properties for individual ring resonators and reliably model their behavior.

Ring resonator model
Ring resonator model

Other people involved:

PhD thesises


    International Journals

  1. A. Kaintura, D. Spina, I. Couckuyt, L.Knockaert, W. Bogaerts, T. Dhaene, A Kriging and Stochastic Collocation ensemble for uncertainty quantification in engineering applications, Engineering with Computers, p.1-15 (2017)  Download this Publication (2.5MB).
  2. A. Li, W. Bogaerts, Fundamental Suppression of Backscattering in Silicon Microrings, Optics Express, (2017)  Download this Publication (2.5MB).
  3. A. Li, T. Van Vaerenbergh, P. De Heyn, P. Bienstman, W. Bogaerts, Backscattering in Silicon Microring Resonators: A Quantitative Analysis, Laser & Photonics Reviews, 10(3), (2016)  Download this Publication (1.3MB).
  4. Y. Xing, D. Spina, A. Li, T. Dhaene, W. Bogaerts, Stochastic Collocation for Device-level Variability Analysis in Integrated Photonics, Photonics Research, (2016)  Download this Publication (782KB).
  5. S. Dwivedi, A. Ruocco, M. Vanslembrouck, T. Spuesens, P. Bienstman, P. Dumon, T. Van Vaerenbergh, W. Bogaerts, Experimental Extraction of Effective Refractive Index and Thermo-Optic Coefficients of Silicon-On-Insulator Waveguides using Interferometers, Journal of Lightwave Technology , 33(21), p.4471 - 4477  (2015)  Download this Publication (854KB).
      International Conferences

    1. W. Bogaerts, Scaling Up Silicon Photonic Circuits: Where Are the Challenges?, International Workshop on Optical/Photonic Interconnects for Computing Systems (OPTICS Workshop) (invited), 3, Switzerland, (2017)  Download this Publication (275KB).
    2. A. Li, Y. Xing, R. Van Laer, R. Baets, W. Bogaerts, Extreme Spectral Transmission Fluctuations in Silicon Nanowires Induced by Backscattering, IEEE International Conference on Group IV Photonics 2016, China, p.paper FB4 (2 pages) (2016)  Download this Publication (2.4MB).
    3. Y. Xing, A. Li, R. Van Laer, R. Baets, W. Bogaerts, Backscatter Model for Nanoscale Silicon Waveguides , 24th International Workshop on Optical Wave & Waveguide Theory and Numerical Modelling (OWTNM 2016), Poland, p.paper OWTNM/O-18 (2016)  Download this Publication (615KB).
    4. A. Li, T. Van Vaerenbergh, P. De Heyn, Y. Xing, P. Bienstman, W. Bogaerts, Experimentally demonstrate the origin for asymmetric resonance splitting and contributions from couplers to backscattering in SOI microrings, Integrated Photonics Research, Silicon and Nano Photonics (IPR 2015), United States, p.IM2B.6 (2015)  Download this Publication (1.4MB).
    5. S. Dwivedi, T. Van Vaerenbergh, A. Ruocco, T. Spuesens, P. Bienstman, P. Dumon, W. Bogaerts, Measurements of Effective Refractive Index of SOI Waveguides using Interferometers, Integrated Photonics Research, Silicon and Nano Photonics (IPR 2015), United States, p.IM2A.6 (2015)  Download this Publication (1.4MB).
    6. A. Ruocco, M. Fiers, M. Vanslembrouck, T. Van Vaerenbergh, W. Bogaerts, Multi-parameter extraction from SOI photonic integrated circuits using circuit simulation and evolutionary algorithms, Proc. SPIE, Smart Photonic and Optoelectronic Integrated Circuits XVII, 9366, United States, p.936606 (2015)  Download this Publication (3.8MB).

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