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Limin Tong - One of the best experts on this subject based on the ideXlab platform.

  • 2D Materials for Optical Modulation: Challenges and Opportunities
    Advanced Materials, 2017
    Co-Authors: Shaoliang Yu, Xiaoqin Wu, Yipei Wang, Xin Guo, Limin Tong
    Abstract:

    Owing to their atomic layer thickness, strong light-material interaction, high nonlinearity, broadband Optical response, fast relaxation, controllable optoelectronic properties, and high compatibility with other photonic structures, 2D materials, including graphene, transition metal dichalcogenides and black phosphorus, have been attracting increasing attention for photonic applications. By tuning the carrier density via electrical or Optical means that modifies their physical properties (e.g., Fermi level or nonlinear absorption), Optical response of the 2D materials can be instantly changed, making them versatile nanostructures for Optical Modulation. Here, up-to-date 2D material-based Optical Modulation in three categories is reviewed: free-space, fiber-based, and on-chip configurations. By analysing cons and pros of different Modulation approaches from material and mechanism aspects, the challenges faced by using these materials for device applications are presented. In addition, thermal effects (e.g., laser induced damage) in 2D materials, which are critical to practical applications, are also discussed. Finally, the outlook for future opportunities of these 2D materials for Optical Modulation is given.

  • Single nanowire ultrafast Optical Modulation and correlation
    2016 IEEE Photonics Society Summer Topical Meeting Series (SUM), 2016
    Co-Authors: Limin Tong
    Abstract:

    Integration of miniaturized elements has been a major driving force behind modern ultrafast photonics. Nanowires have emerged as potential building blocks for compact photonic circuits and devices in nanophotonics. We demonstrate here ultrafast Optical Modulation and correlation on the single-nanowire scale. Based on saturable absorption in graphene films, we show ultrafast Optical Modulation in a graphene flakes doped polymer nanofiber and graphene film coated ZnO nanowire. Also, based on imaging the transverse second harmonic generation (TSHG) from a cadmium sulfide (CdS) and a CdTe nanowires, as well as converting the TSHG spatial image into the temporal profile of the pulses, we demonstrate ultrafast Optical correlation with pulse energy down to femto-joules.

  • Graphene-deposited microfiber for ultrafast Optical Modulation
    2015 Conference on Lasers and Electro-Optics (CLEO), 2015
    Co-Authors: Shaoliang Yu, Limin Tong
    Abstract:

    With a convenient and controllable evanescent-field-induced transfer method, graphene flakes were deposited on the surface of a 1-μm-diameter microfiber, which can be used for ultrafast Optical Modulation based on it's distinct saturable absorption.

  • Graphene decorated microfiber for ultrafast Optical Modulation.
    Optics express, 2015
    Co-Authors: Chao Meng, Bigeng Chen, Hongqing Wang, Wei-tao Liu, Shangjian Zhang, Yong Liu, Limin Tong
    Abstract:

    We demonstrate ultrafast Optical Modulation using a single 1-μm-diameter graphene-decorated microfiber, which is fabricated with a convenient and controllable evanescent-field-induced deposition method. Benefitting from the significantly enhanced light-graphene interaction of the subwavelength transvers dimension of the microfiber and accumulation of the saturable absorption of the piled graphene flakes, the microfiber shows nonlinear saturable absorption with a peak power threshold down to 1.75 W (60 MW/cm2), with a measured response time of about 3.5 ps.

  • Graphene-activated Microfibers and Nanofibers for Ultrafast Optical Modulation
    International Photonics and OptoElectronics Meetings, 2014
    Co-Authors: Limin Tong
    Abstract:

    Based on Optical microfibers or nanofibers coated or doped with graphene flakes, we demonstrate ultrafast Optical Modulation around 1.5-um wavelength with response time down to 2.2 ps and pulse energy down to 0.25 pJ/pulse. Article not available.

Masayuki Izutsu - One of the best experts on this subject based on the ideXlab platform.

Mukesh Kumar - One of the best experts on this subject based on the ideXlab platform.

  • Optical Modulation in Hybrid Waveguide Based on Si-ITO Heterojunction
    Journal of Lightwave Technology, 2020
    Co-Authors: Swati Rajput, Sourabh Jain, Vishal Kaushik, Pragya Tiwari, A. K. Srivastava, Mukesh Kumar
    Abstract:

    An Optical modulator based on a hybrid Optical waveguide made up of Silicon and Indium Tin Oxide (ITO) is proposed. The hybrid waveguide is created by the coupling of a leaky Optical mode guided in silicon with ITO. The Optical Modulation is realized with the heterojunction between p-type silicon and n-type ITO. The presence of ITO causes electrical tuning in permittivity and in imaginary-part of the refractive index which provide a way to modulate the intensity of the guide Optical mode. The device with Si-ITO heterojunction is fabricated to show intensity Modulation at 1.55 μm wavelength. To achieve an efficient Optical Modulation the carrier concentration of ITO is optimized by depositing ITO on p-type Si wafer at different oxygen partial pressures using Ion assisted electro-beam deposition. The fabricated device exhibiting an extinction ratio of 7 dB for 1.7 mm long device at low voltage of −5 volts.

  • Broadband Optical Modulation in a zinc-oxide-based heterojunction via Optical lifting
    Optics Letters, 2020
    Co-Authors: Vishal Kaushik, Swati Rajput, Mukesh Kumar
    Abstract:

    Broadband electro-absorptive Optical Modulation in a zinc-oxide (ZnO)-based heterojunction is demonstrated. The presence of high-density two-dimensional electron gas (2DEG) at the bottom of conduction band offset in a MgZnO-CdZnO heterojunction is shown to exhibit electrically tunable Optical absorption in the regions well below the material bandgap. Electrons confined near the heterojunction are lifted across the potential barrier on Optical excitation. Optical Modulation with an extinction ratio of 8 dB is reported at an operating wavelength of 527 nm. The extinction ratio remains around 7–8 dB over a wide bandwidth of 115 nm, providing an excellent opportunity to explore ZnO-based heterojunctions to realize a broadband Optical modulator for applications in Optical communication and interconnects.

  • Low Group Index Optical Slot Structure for Efficient Optical Modulation
    Conference on Lasers and Electro-Optics, 2020
    Co-Authors: Sourabh Jain, Lalit Singh, Swati Rajput, Mukesh Kumar
    Abstract:

    Optical Modulation based on traveling-wave electrode is proposed using slot-waveguide structure. With the help of high velocity-matching between microwave and Optical modes, high data-rate of 40Gbps with the high extinction ratio of 8.7dB is obtained.

Tetsuya Kawanishi - One of the best experts on this subject based on the ideXlab platform.

Swati Rajput - One of the best experts on this subject based on the ideXlab platform.

  • Optical Modulation in Hybrid Waveguide Based on Si-ITO Heterojunction
    Journal of Lightwave Technology, 2020
    Co-Authors: Swati Rajput, Sourabh Jain, Vishal Kaushik, Pragya Tiwari, A. K. Srivastava, Mukesh Kumar
    Abstract:

    An Optical modulator based on a hybrid Optical waveguide made up of Silicon and Indium Tin Oxide (ITO) is proposed. The hybrid waveguide is created by the coupling of a leaky Optical mode guided in silicon with ITO. The Optical Modulation is realized with the heterojunction between p-type silicon and n-type ITO. The presence of ITO causes electrical tuning in permittivity and in imaginary-part of the refractive index which provide a way to modulate the intensity of the guide Optical mode. The device with Si-ITO heterojunction is fabricated to show intensity Modulation at 1.55 μm wavelength. To achieve an efficient Optical Modulation the carrier concentration of ITO is optimized by depositing ITO on p-type Si wafer at different oxygen partial pressures using Ion assisted electro-beam deposition. The fabricated device exhibiting an extinction ratio of 7 dB for 1.7 mm long device at low voltage of −5 volts.

  • Broadband Optical Modulation in a zinc-oxide-based heterojunction via Optical lifting
    Optics Letters, 2020
    Co-Authors: Vishal Kaushik, Swati Rajput, Mukesh Kumar
    Abstract:

    Broadband electro-absorptive Optical Modulation in a zinc-oxide (ZnO)-based heterojunction is demonstrated. The presence of high-density two-dimensional electron gas (2DEG) at the bottom of conduction band offset in a MgZnO-CdZnO heterojunction is shown to exhibit electrically tunable Optical absorption in the regions well below the material bandgap. Electrons confined near the heterojunction are lifted across the potential barrier on Optical excitation. Optical Modulation with an extinction ratio of 8 dB is reported at an operating wavelength of 527 nm. The extinction ratio remains around 7–8 dB over a wide bandwidth of 115 nm, providing an excellent opportunity to explore ZnO-based heterojunctions to realize a broadband Optical modulator for applications in Optical communication and interconnects.

  • Low Group Index Optical Slot Structure for Efficient Optical Modulation
    Conference on Lasers and Electro-Optics, 2020
    Co-Authors: Sourabh Jain, Lalit Singh, Swati Rajput, Mukesh Kumar
    Abstract:

    Optical Modulation based on traveling-wave electrode is proposed using slot-waveguide structure. With the help of high velocity-matching between microwave and Optical modes, high data-rate of 40Gbps with the high extinction ratio of 8.7dB is obtained.