Prof. Mustapha Hamad Profile

Prof. Mustapha Hamad

at Notre Dame Univ Louaize

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Author

Publications (6)

Proceedings Article | 1 April 2020 Presentation + Paper

Device physical parameters extraction of high-speed VCSELs

Marwan Bou Sanayeh, Wissam Hamad, Mariane Mansour, Reem Al Fata, Elsie Nakhle, Anthony Youssef, Mustapha Hamad, Semaan Georges, Werner Hofmann

Proceedings Volume 11356, 1135619 (2020) https://doi.org/10.1117/12.2555955

KEYWORDS: Vertical cavity surface emitting lasers, Modulation, Data modeling, Mirrors, Optical resonators, Nanophotonics, Efficient operations, Performance modeling

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Realizing that vertical cavity surface emitting lasers (VCSELs) are continuously breaking higher bandwidth limits, it is essential to understand their basic material constituting properties and extract their physical characteristics, in order to fine tune their high-speed performance. Throughout the past decade, the device performance was continuously optimized towards higher bandwidths, faster data rates, and efficient operation. Therefore, for a successful further optimization of their dynamic characteristics, the extraction of a reliable set of their physical parameters becomes indispensable. Consequently, the main objective of this work is to provide accurate physical parameter values of cutting-edge high-speed VCSELs. The extraction process of these set of parameters is based on the novel intrinsic and extrinsic dynamic models that were recently developed by our research group. For the intrinsic dynamics, the advanced split carrier reservoir multimode model is employed. Furthermore, the pure intrinsic modulation response is de-embedded from the total measured device response using our recently proposed novel parasitic-network model. Moreover, the extraction of these device physical parameters is based on the device’s performance indicators, such as the relaxation oscillation frequencies and damping coefficients obtained by fitting the intrinsic model to the measured modulation data. Furthermore, since these performance indicators can be expressed in terms of a combination of these physical parameters, a precise estimation of their values and their possible ranges, along with a carefully designed fitting process, is crucial. Consequently, for extracting a reliable set of data, the accurate prior estimation of these parameters was conducted based on the device physical structure and reported material properties, leading to the establishment of an accurate set of parameters along with their possible ranges. These final calculations are based on simple device geometrical considerations, reported physical and material properties and device static performance measurements. Finally, the estimated values and their ranges are further validated by comparing them to ones in standard literature.

Proceedings Article | 6 November 2018 Paper

Advanced modulation response analysis of high-speed VCSELs

Wissam Hamad, Marwan Bou Sanayeh, Mustapha Hamad, Werner Hofmann

Proceedings Volume 10812, 108120N (2018) https://doi.org/10.1117/12.2501216

KEYWORDS: Vertical cavity surface emitting lasers, Modulation, Analytical research, Diffusion, Performance modeling, Nanophotonics, Data modeling, Solid state physics, Modulation transfer functions, Phase modulation

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Proceedings Article | 6 November 2018 Paper

Modulation response, impedance, and equivalent circuit of ultra-high-speed multi-mode VCSELs

Wissam Hamad, Marwan Bou Sanayeh, Bassel Aboul Hosn, Vana Ajemian, Rami Yehia, Eliane Zouein, Mustapha Hamad, Werner Hofmann

Proceedings Volume 10812, 1081203 (2018) https://doi.org/10.1117/12.2500166

KEYWORDS: Vertical cavity surface emitting lasers, Circuit switching, Modulation, Data modeling, Capacitance, Oxides, Resistance, Microwave radiation, Capacitors, Device simulation

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Proceedings Article | 9 May 2018 Paper

De-embedding device parasitics of ultra-high speed VCSELs

Wissam Hamad, Nataly Dalal, Serena Bou Nassar, Marwan Bou Sanayeh, Mustapha Hamad, Werner Hofmann

Proceedings Volume 10682, 106821T (2018) https://doi.org/10.1117/12.2306920

KEYWORDS: Vertical cavity surface emitting lasers, Data modeling, Modeling

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To establish highly performing vertical cavity surface-emitting lasers (VCSELs), it is essential to have an adequate understanding of the intrinsic laser dynamics of these devices. However, this is done while bearing in mind that extrinsic parasitic elements in VCSELs play an important role in limiting the intrinsic modulation bandwidth. In this work, we analyse different electrical parasitic equivalent circuit models in the aim of comparing them and selecting the one that can best describe and represent the physical properties of our high-performance VCSELs. Through measuring the microwave reflection coefficient S₁₁(f), then fitting it with the calculated one from the equivalent circuit impedance model, the parasitic components of the equivalent circuit model can be extracted. The S₁₁(f) data was collected over different ranges of operating bias currents and using a 7 μm oxide aperture diameter VCSEL. This allows us to observe the variations of these circuit elements with respect to the current and compute the transfer function and the resulting parasitic cut-off frequencies (bandwidth limitation) for each model. After plotting and comparing the transfer functions of the different models together, under the same driving current, it was found that the discrepancy between the two curves, in a specific frequency range, is rather small over the VCSEL bandwidth of interest, hence allowing us to use the first-order low pass filter to de-embed the parasitic contributions and separate them from the device intrinsic response. However, over higher frequency ranges, the deviation is found to be substantial and the extract parasitic transfer function should be taken into consideration.

Another issue to be addressed is the reliability of the simple circuit models to extract accurate circuit component values, especially when the deviation between the measured microwave reflection coefficient S₁₁(f) and the fitted model is substantially large. This discrepancy is due to the oversimplification imposed on the equivalent circuit model, leading to a high level of uncertainty in the extracted circuit component values. Thus, sufficient modelling and accurate fitting strategies are needed for a reliable parasitic de-embedding approach.

Proceedings Article | 9 May 2018 Paper

Equivalent circuit modeling of the dynamic operation of ultra-high speed multi-mode VCSELs

Wissam Hamad, Elio Nakhle, Oliver Daou, Marwan Bou Sanayeh, Mustapha Hamad, Werner Hofmann

Proceedings Volume 10682, 106821R (2018) https://doi.org/10.1117/12.2306823

KEYWORDS: Vertical cavity surface emitting lasers, Modulation, Data modeling, Device simulation, Performance modeling, Modeling, Solid state physics

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Proceedings Article | 17 May 2017 Paper

Small-signal analysis of ultra-high-speed 30 GHz VCSELs using an advanced multi-mode approach

Wissam Hamad, Marwan Bou Sanayeh, Hassan Hamad, Mustapha Hamad, Semaan Georges, Werner Hofmann

Proceedings Volume 10242, 102420Y (2017) https://doi.org/10.1117/12.2265834

KEYWORDS: Mathematical modeling, Solid state physics, Nanophotonics, Vertical cavity surface emitting lasers, Modulation, Data modeling, Optical interconnects, Mirrors, Data communications, Physics, Analytical research, Binary data

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