Browsing NTNU Open by Author "Ballato, John"

Now showing items 1-20 of 28

    • All-fibre heterogeneously-integrated frequency comb generation using silicon core fibre 

      Sohanpal, Ronit; Ren, Haonan; Deakin, Callum; Heidt, Alexander; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula; Peacock, Anna; Liu, Zhixin (Peer reviewed; Journal article, 2022)
      Originally developed for metrology, optical frequency combs are becoming increasingly pervasive in a wider range of research topics including optical communications, spectroscopy, and radio or microwave signal processing. ...

    • All-optical high-speed modulation of THz transmission through silicon core optical fibers 

      Sørgård, Trygve Reinertsen; Hawkins, Thomas; Ballato, John; Österberg, Ulf Lennart; Gibson, Ursula (Journal article; Peer reviewed, 2021)
      High speed optical modulation of THz radiation is of interest for information processing and communications applications. In this paper infrared femtosecond pulses are used to generate free carriers that reduce the THz ...

    • Broadband infrared and THz transmitting silicon core optical fiber 

      Sørgård, Trygve; Song, Seunghan; Vullum, Per Erik; Kores, Cristine; Mølster, Kjell Martin; Laurell, Fredrik; Hawkins, Thomas A.; Ballato, John; Österberg, Ulf Lennart; Gibson, Ursula (Peer reviewed; Journal article, 2020)
      Silicon waveguide structures are a viable alternative for the transmission of signals over a wide range of frequencies, and new fabrication methods are key to increased applications. In this work, THz transparency of ...

    • Bulk fabrication and properties of solar grade silicon microwires 

      Martinsen, Fredrik A; Ballato, John; Hawkins, Thomas A.; Gibson, Ursula (Journal article; Peer reviewed, 2014)
      We demonstrate a substrate-free novel route for fabrication of solar grade silicon microwires for photovoltaic applications. The microwires are fabricated from low purity starting material via a bulk molten-core fibre ...

    • Characterisation of Silicon (Si) fibre Bragg grating in near-infrared band for strain and temperature sensing 

      Theodosiou, Antreas; Kalli, Kyriacos; Hawkins, Thomas A.; Ballato, John; Fokine, Michael; Gibson, Ursula (Journal article; Peer reviewed, 2018)
      This letter describes fibre Bragg grating inscription in crystalline siliconcore fibre using visible light femtosecond laser pulses. The femtosecond pulses at 517 nm propagate through the transparent silica glass cladding ...

    • CO2 laser annealed SiGe core optical fibers with radial Ge concentration gradients 

      Wu, Wei; Balci, Mustafa H.; Song, Seunghan; liu, chunxin; Fokine, Michael; Laurell, Fredrik; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula (Peer reviewed; Journal article, 2020)
      CO2 laser annealing of SiGe core, glass-clad optical fibers is a powerful technique for the production of single-crystal cores with spatially varying Ge concentrations. Laser power, laser scan speed and cooling air flow ...

    • Continuous-wave Raman amplification in silicon core fibers pumped in the telecom band 

      Huang, Meng; Sun, Shiyu; Wu, Dong; Ren, Haonan; Shen, Li; Hawkins, Thomas; Ballato, John; Gibson, Ursula; Peacock, Anna C. (Peer reviewed; Journal article, 2021)
      Stimulated Raman amplification is observed for the first time in the silicon core fiber (SCF) platform. The SCFs were tapered to obtain sub-micrometer core dimensions and low optical transmission losses, facilitating ...

    • Core opportunities for future optical fibers 

      Ballato, John; Gibson, Ursula (Journal article; Peer reviewed, 2021)

    • Crystalline GaSb-core optical fibers with room-temperature photoluminescence 

      Song, Seunghan; Healy, Noel; Svendsen, Silje; Österberg, Ulf; Cuervo Covian, Alejandra; Liu, Jifeng; Peacock, Anna; Ballato, John; Laurell, Fredrik; Fokine, Michael; Gibson, Ursula (Journal article; Peer reviewed, 2018)
      Glass-clad, GaSb-core fibers were drawn and subsequently laser annealed. The asdrawn fibers were found to be polycrystalline, possess Sb inclusions, and have oxide contamination concentrations of less than 3 at%. Melting ...

    • Fiber Integrated Wavelength Converter Based on a Silicon core Fiber with a Nano-spike cCoupler 

      Huang, Meng; Ren, Haonan; Aktas, Ozan; Shen, Li; Wang, Jiang; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula; Peacock, Anna (Journal article; Peer reviewed, 2019)
      Abstract—An all-fiber integrated nonlinear silicon photonicwavelength converter has been proposed and fabricated using thesilicon core fiber platform. The silicon fiber was spliced directly toa conventional single ...

    • Four-wave Mixing-based Wavelength Conversion and Parametric Amplification in Submicron Silicon Core Fibers 

      Wu, Dong; Shen, Li; Ren, Haonan; Huang, Meng; Lacava, Cosimo; Campling, Joseph; Sun, Shiyu; Hawkins, Thomas A.; Gibson, Ursula; Petropoulos, Periklis; Ballato, John; Peacock, Anna (Peer reviewed; Journal article, 2020)
      Silicon core fibers represent a versatile platform for all-fiber integrated nonlinear optical applications. This paper describes the state of the art in four-wave mixing-based parametric amplification, and wavelength ...

    • Ge-capped SiGe core optical fibers 

      Wu, Wei; Balci, Mustafa H.; Muhlberger, Korbinian; Fokine, Michael; Laurell, Fredrik; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula (Journal article; Peer reviewed, 2019)
      CO2 laser processing offers the possibility to inscribe structures within glass-clad SiGe-core fibers by altering the spatial distribution of the Si and Ge. Spatial segregation of Ge to the end of a fiber is shown via ...

    • Kerr nonlinear switching in a hybrid silica-silicon microspherical resonator 

      Suhailin, Fariza; Healy, N; Franz, Y; Sumetsky, Misha; Ballato, John; Dibbs, Andrew; Gibson, Ursula; Peacock, Anna (Journal article; Peer reviewed, 2015)
      A hybrid silicon-core, silica-clad microspherical resonator has been fabricated from the semiconductor core fiber platform. Linear and nonlinear characterization of the resonator properties have shown it to exhibit ...

    • Laser recrystallization and inscription of compositional microstructures in crystalline SiGe-core fibres 

      Coucheron, David Andre; Fokine, Michael; Patil, Nilesh; Breiby, Dag Werner; Buset, Ole Tore; Healy, Noel; Peacock, Anna; Hawkins, Thomas A.; Jones, Maxwell; Ballato, John; Gibson, Ursula (Journal article; Peer reviewed, 2016)
      Glass fibres with silicon cores have emerged as a versatile platform for all-optical processing, sensing and microscale optoelectronic devices. Using SiGe in the core extends the accessible wavelength range and potential ...

    • Laser restructuring and photoluminescence of glass-clad GaSb/Si-core optical fibres 

      Song, Seunghan; Lønsethagen, Kristin; Laurell, Fredrik; Hawkins, Thomas A.; Ballato, John; Fokine, Michael; Gibson, Ursula (Journal article; Peer reviewed, 2019)
      Semiconductor-core optical fibres have potential applications in photonics and optoelectronics due to large nonlinear optical coefficients and an extended transparency window. Laser processing can impose large temperature ...

    • Laser structuring, stress modification and Bragg grating inscription in silicon-core glass fibers 

      Fokine, Michael; Theodosiou, Antreas; Song, Seunghan; Hawkins, Thomas A.; Ballato, John; Kalli, Kyriacos; Gibson, Ursula (Journal article; Peer reviewed, 2017)
      Semiconductor core fibers have numerous potential applications in optoelectronics and photonics, and the key to realizing these opportunities is controlled processing of the material. We present results on laser treatments ...

    • Light trapping in horizontally aligned silicon microwire solar cells 

      Martinsen, Fredrik Aleksander; Smeltzer, Benjamin; Ballato, John; Jones, Maxwell; Hawkins, Thomas A.; Gibson, Ursula (Journal article; Peer reviewed, 2015)
      In this study, we demonstrate a solar cell design based on horizontally aligned microwires fabricated from 99.98% pure silicon via the molten core fiber drawing method. A similar structure consisting of 50 μm diameter close ...

    • Localised structuring of metal-semiconductor cores in silica clad fibres using laser-driven thermal gradients 

      Song, Seunghan; Laurell, Fredrik; Meehan, Bailey; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula (Peer reviewed; Journal article, 2022)
      The molten core drawing method allows scalable fabrication of novel core fibres with kilometre lengths. With metal and semiconducting components combined in a glass-clad fibre, CO2 laser irradiation was used to write ...

    • Low-loss silicon core fibre platform for mid-infrared nonlinear photonics 

      Ren, Haonan; Shen, Li; Runge, Antoine; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula; Peacock, Anna (Journal article; Peer reviewed, 2019)
      Broadband mid-infrared light sources are highly desired for wide-ranging applications that span free-space communications to spectroscopy. In recent years, silicon has attracted great interest as a platform for nonlinear ...

    • Material properties of tapered crystalline silicon core fibers 

      Franz, Yohann; Runge, A. F.; Ren, Haonan; Healy, Noel; Ignatyev, K.; Jones, Maxwell; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula; Peacock, Anna (Journal article; Peer reviewed, 2017)
      Crystalline silicon optical fibers are emerging as a promising platform for a wide range of optoelectronic applications. Here we report a crystallographic study of the material properties within silicon fibers that have ...