• 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 ...
    • 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 ...
    • 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 ...
    • Nonlinear optical properties of polycrystalline silicon core fibers from telecom wavelengths into the mid-infrared spectral region 

      Ren, Haonan; Shen, Li; Wu, D; Aktas, Ozan; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula; Peacock, Anna (Journal article; Peer reviewed, 2019)
      Polycrystalline silicon core fibers (SCFs) fabricated via the molten core drawing (MCD) method are emerging as a flexible optoelectronic platform. Here, the optical transmission properties of MCD SCFs that have been tapered ...
    • Silicon Optical Fibres - Past, Present and Future 

      Peacock, Anna; Gibson, Ursula; Ballato, John (Journal article; Peer reviewed, 2016)
      This paper reviews the past, present and prospective future of silicon optical fibres. The incorporation of silicon with its rich optoelectronic functionality into existing glass fibre technologies presents a route to ...
    • Silicon-core glass fibres as microwire radial-junction solar cells 

      Martinsen, Fredrik A; Smeltzer, Benjamin; Nord, Magnus Kristofer; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula (Journal article; Peer reviewed, 2014)
      Vertically aligned radial-junction solar cell designs offer potential improvements over planar geometries, as carrier generation occurs close to the junction for all absorption depths, but most production methods still ...
    • Single crystal semiconductor-core optical fiber* 

      Wu, Wei; Song, Seunghan; Balci, Mustafa H.; Laurell, Fredrik; Cantwell, Patrick; Ballato, John; Gibson, Ursula (Journal article; Peer reviewed, 2019)
      Semiconductor-core fibers are improved by removal of grain boundaries. We use a CO2 laser to process silicon-based cores; an alloying element reduces both the temperature and speed required for formation of a single crystal.
    • Tapered silicon core fibers with nano-spikes for optical coupling via spliced silica fibers 

      Ren, Haonan; Aktas, Ozan; Franz, Yohann; Runge, Antoine; Hawkins, Thomas A.; Ballato, John; Gibson, Ursula; Peacock, Anna (Journal article; Peer reviewed, 2017)
      Abstract: Reported here is the fabrication of tapered silicon core fibers possessing a nanospike input that facilitates their seamless splicing to conventional single mode fibers. A proofof-concept 30 µm cladding diameter ...