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Amr S. Helmy - One of the best experts on this subject based on the ideXlab platform.

  • generation of polarization entangled photon pairs in a Bragg Reflection waveguide
    Optics Express, 2013
    Co-Authors: Adam Valles, Amr S. Helmy, Dongpeng Kang, Payam Abolghasem, B. J. Bijlani, Martin Hendrych, Jiři Svozilik, Radek Machulka, Juan P Torres
    Abstract:

    We demonstrate experimentally that spontaneous parametric down-conversion in an AlxGa1−xAs semiconductor Bragg Reflection waveguide can make for paired photons highly entangled in the polarization degree of freedom at the telecommunication wavelength of 1550 nm. The pairs of photons show visibility higher than 90% in several polarization bases and violate a Clauser-Horne-Shimony-Holt Bell-like inequality by more than 3 standard deviations. This represents a significant step toward the realization of efficient and versatile self pumped sources of entangled photon pairs on-chip.

  • single sided Bragg Reflection waveguides with multilayer core for monolithic semiconductor parametric devices
    Journal of The Optical Society of America B-optical Physics, 2012
    Co-Authors: Payam Abolghasem, Amr S. Helmy
    Abstract:

    We propose and examine single-stack matching-layer enhanced Bragg Reflection waveguides (BRWs) as a platform for integrated parametric devices. The proposed designed is asymmetric in geometry, where a multilayer core is surrounded by a single-layer upper cladding and a lower quarter-wave Bragg mirror. The propagation of the Bragg mode in the new design relies on total internal Reflection from the upper cladding and Bragg Reflection from the lower periodic cladding. Analytical expressions for modal analysis of TE- and TM-polarized Bragg modes are derived. An AlxGa1−xAs second-harmonic generation device is theoretically examined to highlight nonlinear performance of the new design, and it is compared to symmetric phase-matched BRWs reported to date. The application of the same structure for generation of anticorrelated photon pairs is discussed.

  • far field of Bragg Reflection waveguides characteristics and closed form approximation
    Journal of Lightwave Technology, 2011
    Co-Authors: Nima Zareian, Payam Abolghasem, Amr S. Helmy
    Abstract:

    A comprehensive study of the far-field diffraction pattern of Bragg Reflection waveguides is presented. Using a Gaussian approximation of the near-field profile, an analytical formula for the far-field pattern of the fundamental Bragg mode is obtained. The proposed closed-form representation offers a powerful technique for examining the far-field characteristics, which provides insight into the design optimization of Bragg Reflection waveguides.

  • Mode Selectivity in Bragg Reflection Waveguide Lasers
    IEEE Photonics Technology Letters, 2011
    Co-Authors: Cunzhu Tong, Bhavin J. Bijlani, L. J. Zhao, Sanaz Alali, Q Han, Amr S. Helmy
    Abstract:

    Bragg Reflection waveguides (BRWs) have recently been proposed for the development of high performance single mode lasers and nonlinear frequency conversion devices. In this letter, we experimentally demonstrate single transverse photonic bandgap mode operation in a large core BRW laser with low threshold current density (~594 A/cm2) and high characteristic temperature (T0 ~ 175 K). The mode selectivity is examined theoretically using the effective index method and experimentally via far field and gain spectra measurements. Mode competition is found to take place among the lateral modes despite the optical thickness of the core layer being larger than the wavelength.

  • Type-0 Spontaneous Parametric Down Conversion in AlGaAs Bragg Reflection Waveguides
    CLEO:2011 - Laser Applications to Photonic Applications, 2011
    Co-Authors: Rolf Horn, Amr S. Helmy, Payam Abolghasem, B. J. Bijlani, Gregor Weihs
    Abstract:

    By analyzing the time correlation between two single photon detector events, we demonstrate Spontaneous Parametric Down Conversion of a picosecond pulsed laser in an AlGaAs ridge Bragg Reflection Waveguide.

Payam Abolghasem - One of the best experts on this subject based on the ideXlab platform.

  • Entanglement in a Bragg Reflection waveguide
    CLEO: 2014, 2014
    Co-Authors: Rolf Horn, Piotr Kolenderski, Dongpeng Kang, Payam Abolghasem, Lukas G. Helt, Sergei V. Zhukovsky, Carmelo Scarcella, Adriano Della Frera, Alberto Tosi, John E. Sipe
    Abstract:

    We demonstrate that an integrated photonic Bragg Reflection waveguide (BRW) inherently produces polarization entangled photons.

  • generation of polarization entangled photon pairs in a Bragg Reflection waveguide
    Optics Express, 2013
    Co-Authors: Adam Valles, Amr S. Helmy, Dongpeng Kang, Payam Abolghasem, B. J. Bijlani, Martin Hendrych, Jiři Svozilik, Radek Machulka, Juan P Torres
    Abstract:

    We demonstrate experimentally that spontaneous parametric down-conversion in an AlxGa1−xAs semiconductor Bragg Reflection waveguide can make for paired photons highly entangled in the polarization degree of freedom at the telecommunication wavelength of 1550 nm. The pairs of photons show visibility higher than 90% in several polarization bases and violate a Clauser-Horne-Shimony-Holt Bell-like inequality by more than 3 standard deviations. This represents a significant step toward the realization of efficient and versatile self pumped sources of entangled photon pairs on-chip.

  • single sided Bragg Reflection waveguides with multilayer core for monolithic semiconductor parametric devices
    Journal of The Optical Society of America B-optical Physics, 2012
    Co-Authors: Payam Abolghasem, Amr S. Helmy
    Abstract:

    We propose and examine single-stack matching-layer enhanced Bragg Reflection waveguides (BRWs) as a platform for integrated parametric devices. The proposed designed is asymmetric in geometry, where a multilayer core is surrounded by a single-layer upper cladding and a lower quarter-wave Bragg mirror. The propagation of the Bragg mode in the new design relies on total internal Reflection from the upper cladding and Bragg Reflection from the lower periodic cladding. Analytical expressions for modal analysis of TE- and TM-polarized Bragg modes are derived. An AlxGa1−xAs second-harmonic generation device is theoretically examined to highlight nonlinear performance of the new design, and it is compared to symmetric phase-matched BRWs reported to date. The application of the same structure for generation of anticorrelated photon pairs is discussed.

  • far field of Bragg Reflection waveguides characteristics and closed form approximation
    Journal of Lightwave Technology, 2011
    Co-Authors: Nima Zareian, Payam Abolghasem, Amr S. Helmy
    Abstract:

    A comprehensive study of the far-field diffraction pattern of Bragg Reflection waveguides is presented. Using a Gaussian approximation of the near-field profile, an analytical formula for the far-field pattern of the fundamental Bragg mode is obtained. The proposed closed-form representation offers a powerful technique for examining the far-field characteristics, which provides insight into the design optimization of Bragg Reflection waveguides.

  • Tailoring the Far Field of Bragg Reflection Waveguides
    Advanced Photonics, 2011
    Co-Authors: Nima Zareian, Payam Abolghasem, Amr S. Helmy
    Abstract:

    A comprehensive study of the far field of Bragg Reflection waveguides is presented. Insight obtained by a newly developed Gaussian approximation of the near field provides a valuable tool for optimizing the far-field pattern.

B. J. Bijlani - One of the best experts on this subject based on the ideXlab platform.

  • generation of polarization entangled photon pairs in a Bragg Reflection waveguide
    Optics Express, 2013
    Co-Authors: Adam Valles, Amr S. Helmy, Dongpeng Kang, Payam Abolghasem, B. J. Bijlani, Martin Hendrych, Jiři Svozilik, Radek Machulka, Juan P Torres
    Abstract:

    We demonstrate experimentally that spontaneous parametric down-conversion in an AlxGa1−xAs semiconductor Bragg Reflection waveguide can make for paired photons highly entangled in the polarization degree of freedom at the telecommunication wavelength of 1550 nm. The pairs of photons show visibility higher than 90% in several polarization bases and violate a Clauser-Horne-Shimony-Holt Bell-like inequality by more than 3 standard deviations. This represents a significant step toward the realization of efficient and versatile self pumped sources of entangled photon pairs on-chip.

  • Type-0 Spontaneous Parametric Down Conversion in AlGaAs Bragg Reflection Waveguides
    CLEO:2011 - Laser Applications to Photonic Applications, 2011
    Co-Authors: Rolf Horn, Amr S. Helmy, Payam Abolghasem, B. J. Bijlani, Gregor Weihs
    Abstract:

    By analyzing the time correlation between two single photon detector events, we demonstrate Spontaneous Parametric Down Conversion of a picosecond pulsed laser in an AlGaAs ridge Bragg Reflection Waveguide.

  • difference frequency generation in algaas Bragg Reflection waveguides
    Optics Letters, 2010
    Co-Authors: Junbo Han, Payam Abolghasem, Dongpeng Kang, B. J. Bijlani, Amr S. Helmy
    Abstract:

    We demonstrate Type II difference-frequency generation (DFG) around 1550nm in AlGaAs Bragg Reflection waveguides using a pump around 778nm and a signal within the C-band range. Difference-frequency power of 0.95nW was obtained using a pump power of 62.9mW and a signal power of 2.9mW. Nonlinear conversion efficiency was estimated to be 2.5×10−2%/W−1cm−2 in a 1.5-mm-long sample. Using numerical simulations, the phase-matching bandwidth was predicted to be 100nm, while the measured DFG showed no sign of bandwidth limitation across a wavelength span of 40nm, which was limited by instrumentation.

  • femtosecond second harmonic generation in algaas Bragg Reflection waveguides theory and experiment
    Journal of The Optical Society of America B-optical Physics, 2010
    Co-Authors: Junbo Han, Payam Abolghasem, B. J. Bijlani, Arghavan Arjmand, Chaitanya S Kumar, A Estebanmartin, M Ebrahimzadeh, Amr S. Helmy
    Abstract:

    The impact of third-order nonlinearities including self-phase modulation and two-photon absorption on the efficiency of the second-harmonic generation is numerically investigated using the split-step Fourier method in phase-matched Bragg Reflection waveguides. Also using the same technique, the adverse effects of group velocity mismatch and group velocity dispersion of the interacting frequencies on the efficiency of the nonlinear process are examined and contrasted for optimal sample design. Using an optimized structure, we report efficient femtosecond second-harmonic generation in monolithic AlGaAs Bragg Reflection waveguides for a type II nonlinear interaction. For a 190 fs pulsed pump around 1555 nm with an average power of 3.3 mW, a peak second-harmonic power of 25.5  μW is measured in a sample with a length of 1.1 mm. The normalized conversion efficiency of the process is estimated to be 2.0×104% W−1 cm−2. Pump depletion is clearly observed when operating at the phase-matching wavelength.

  • CW single photonic bandgap mode operation in Bragg Reflection waveguide lasers
    2010 IEEE Photinic Society's 23rd Annual Meeting, 2010
    Co-Authors: Cunzhu Tong, L. J. Zhao, Sanaz Alali, B. J. Bijlani, Han Qin, Amr S. Helmy
    Abstract:

    Continuous wave single vertical transverse photonic bandgap mode operation in a large core (700 nm) Bragg Reflection waveguide laser with low threshold current (594A/cm2) was demonstrated. The transverse mode competition was analyzed in detail.

Gregor Weihs - One of the best experts on this subject based on the ideXlab platform.

  • temporally versatile polarization entanglement from Bragg Reflection waveguides
    Optics Letters, 2017
    Co-Authors: A Schlager, K. Laiho, Sven Höfling, B Pressl, H Suchomel, Martin Kamp, Christian Schneider, Gregor Weihs
    Abstract:

    Bragg Reflection waveguides emitting broadband parametric downconversion (PDC) have been proven to be well suited for the on-chip generation of polarization entanglement in a straightforward fashion [Sci. Rep.3, 2314 (2013)SRWSDA2045-232210.1038/srep02314]. Here, we investigate how the properties of the created states can be modified by controlling the relative temporal delay between the pair of photons created via PDC. Our results offer an easily accessible approach for changing the coherence of the polarization entanglement, in other words, to tune the phase of the off-diagonal elements of the density matrix. Furthermore, we provide valuable insight into the engineering of these states directly at the source.

  • mode resolved fabry perot experiment in low loss Bragg Reflection waveguides
    Optics Express, 2015
    Co-Authors: Benedikt Pressl, T. Günthner, Sven Höfling, Martin Kamp, Christian Schneider, Kaisa Laiho, J Gesler, Gregor Weihs
    Abstract:

    Based on the interaction between different spatial modes, semiconductor Bragg-Reflection waveguides (BRWs) provide a highly functional platform for non-linear optics. For achieving any desired quantum optical functionality, we must control and engineer the properties of each spatial mode. To reach this purpose we extend the Fabry-Perot technique and achieve a detailed linear optical characterization of dispersive multimode semiconductor waveguides. With this efficient broadband spectral method we gain direct experimental access to the relevant modes of our BRWs and determine their group velocities. Furthermore, we show that our waveguides have lower than expected loss coefficients. This renders them suitable for integrated quantum optics applications.

  • Characteristics of parametric downconversion from a Bragg-Reflection waveguide
    arXiv: Quantum Physics, 2014
    Co-Authors: T. Günthner, Benedikt Pressl, K. Laiho, J. Geßler, Sven Höfling, M. Kamp, C. Schneider, Gregor Weihs
    Abstract:

    We investigate the properties of co-propagating twin beams created by parametric downconversion in a ridge Bragg-Reflection waveguide. Our source is bright and efficient although the tightly confined waveguide modes are not perfectly compatible with standard single-mode fibre optics. We observe the coalesce of the twin beams and investigate the effect of the multi-photon contributions on the observed photon bunching. Our source shows a great potential for producing indistinguishable photon pairs as well as multi-photon states.

  • Type-0 Spontaneous Parametric Down Conversion in AlGaAs Bragg Reflection Waveguides
    CLEO:2011 - Laser Applications to Photonic Applications, 2011
    Co-Authors: Rolf Horn, Amr S. Helmy, Payam Abolghasem, B. J. Bijlani, Gregor Weihs
    Abstract:

    By analyzing the time correlation between two single photon detector events, we demonstrate Spontaneous Parametric Down Conversion of a picosecond pulsed laser in an AlGaAs ridge Bragg Reflection Waveguide.

Junbo Han - One of the best experts on this subject based on the ideXlab platform.

  • difference frequency generation in algaas Bragg Reflection waveguides
    Optics Letters, 2010
    Co-Authors: Junbo Han, Payam Abolghasem, Dongpeng Kang, B. J. Bijlani, Amr S. Helmy
    Abstract:

    We demonstrate Type II difference-frequency generation (DFG) around 1550nm in AlGaAs Bragg Reflection waveguides using a pump around 778nm and a signal within the C-band range. Difference-frequency power of 0.95nW was obtained using a pump power of 62.9mW and a signal power of 2.9mW. Nonlinear conversion efficiency was estimated to be 2.5×10−2%/W−1cm−2 in a 1.5-mm-long sample. Using numerical simulations, the phase-matching bandwidth was predicted to be 100nm, while the measured DFG showed no sign of bandwidth limitation across a wavelength span of 40nm, which was limited by instrumentation.

  • femtosecond second harmonic generation in algaas Bragg Reflection waveguides theory and experiment
    Journal of The Optical Society of America B-optical Physics, 2010
    Co-Authors: Junbo Han, Payam Abolghasem, B. J. Bijlani, Arghavan Arjmand, Chaitanya S Kumar, A Estebanmartin, M Ebrahimzadeh, Amr S. Helmy
    Abstract:

    The impact of third-order nonlinearities including self-phase modulation and two-photon absorption on the efficiency of the second-harmonic generation is numerically investigated using the split-step Fourier method in phase-matched Bragg Reflection waveguides. Also using the same technique, the adverse effects of group velocity mismatch and group velocity dispersion of the interacting frequencies on the efficiency of the nonlinear process are examined and contrasted for optimal sample design. Using an optimized structure, we report efficient femtosecond second-harmonic generation in monolithic AlGaAs Bragg Reflection waveguides for a type II nonlinear interaction. For a 190 fs pulsed pump around 1555 nm with an average power of 3.3 mW, a peak second-harmonic power of 25.5  μW is measured in a sample with a length of 1.1 mm. The normalized conversion efficiency of the process is estimated to be 2.0×104% W−1 cm−2. Pump depletion is clearly observed when operating at the phase-matching wavelength.

  • Broadband difference-frequency generation in AlGaAs Bragg Reflection waveguides
    2010 IEEE Photinic Society's 23rd Annual Meeting, 2010
    Co-Authors: Junbo Han, Payam Abolghasem, Dongpeng Kang, B. J. Bijlani, Amr S. Helmy
    Abstract:

    Type-II difference-frequency generation with a bandwidth exceeding 40 nm was obtained in AlGaAs Bragg Reflection waveguide. The external normalized conversion efficiency of 2.5 × 10−2 %W−1cm−2 was obtained in a 1.5 mm long device.

  • Broadband sum-frequency generation in AlGaAs Bragg Reflection waveguides
    Conference on Lasers and Electro-Optics 2010, 2010
    Co-Authors: Junbo Han, B. J. Bijlani, Payam Abolghasem, Amr S. Helmy
    Abstract:

    Efficient continuous-wave sum-frequency generation with a bandwidth exceeding 60 nm was obtained in AlGaAs Bragg-Reflection waveguide for type-II nonlinear interaction. Normalized conversion efficiency of 317 %W−1cm−2 was estimated in a device with 2.2 mm length.

  • Wavelength conversion in Bragg Reflection waveguides
    2010 Photonics Global Conference, 2010
    Co-Authors: Junbo Han, Payam Abolghasem, Dongpeng Kang, B. J. Bijlani, Amr S. Helmy
    Abstract:

    We demonstrate continuous wave wavelength conversion between the near-IR) and mid-IR wavelength regimes based on sum-frequency generation (SFG) and difference-frequency generation (DFG) processes. Phase-matching (PM) is achieved for type-II nonlinear interaction using Bragg Reflection waveguides. The normalized external conversion efficiency is estimated to be 26 %W−1 cm−2 for SFG in a 2.2 mm device and 5.8×10−2 %W−1 cm−2 for DFG in a 1.5 mm device. The PM bandwidths of the SFG and DFG processes were found to exceed 60 nm and 40 nm, respectively, which were limited by instrumentation.