Dual suspended core optical fibre
Dual suspended core optical fibre was fabricated and demonstrated by researchers at the Optoelectronics Research Centre in the UK. This fibre has unique function that any other fibres not able to achieve easily, not only transmit light, also the two cores can mechanically move and interact with each other. This MEMS-type of optical fibre was made from lead silicate glass.
The submicron optical fibre is highly sensitive to pressure, vibration etc. and would offer interesting applications in the broad field of sensing.
[http://www.osa.org/about_osa/newsroom/newsreleases/2012/new_dynamic_dual-core_optical_fiber_enhances_data/]
Cane-in-tube method for optical fiber fabrications
Microstructured optical fibers (MOFs) can be made entirely from one type of glass as they do not rely on dopants for guidance. MOFs include mainly two type of fibers: (1) Holey fibers, in which the core is solid and light is guided by a modified form of total internal reflection as the air holes lower the effective refractive index of the cladding relative to that of the solid core. (2) Photonic band-gap fibers, in which guidance in a hollow core can be achieved via photonic band-gap effects. [www.orc.soton.ac.uk, Advanced Fibre Technologies & Applications Group].
[Image from Max Planck Institute, Photonics & New Materials, http://www.mpl.mpg.de]
To fabricate MOFs, capillaries need to be drawn (or can be purchased, but material purities varies, depends on the suppliers) first. Those capillaries then stacked as a preform (normally hexagonal mesh structure). The preform will then be caned down to smaller diameter and finally be slotted into a prepared tube (outer cladding). A typically less than 200 µm fiber will be drawn from the final preform.
Cane-in-tube method is also used for other structures such as fiber with suspended core [Monro, Progress in Microstructured Optical Fibers, Annu. Rev. Mater. Res 2006. 36. 467-95]; and for different materials (other compound glasses, lead silicate or Chalcogenide glasses [Lian,zhenggang Solid Microstructured Chalcogenide Glass Optical Fibers for the Near- and Mid-Infrared Spectral Regions, IEEE PTL, Vol.21, No. 24, 1804-1806, 2009]).
http://ioptic.blogspot.com/2011/08/high-speed-fiber-optics-for.html
Ultra high speed fiber optics for communication tend to generate much attention due to nowadays internet usage is largely maximized (probably youtube takes much of the internet bandwidth). Companies such as Google is now plan to build very high speed fibre to home:
http://www.google.com/appserve/fiberrfi/
Silica glass single mode optical fiber used for communication at the moment using wavelength 1550 nm, the reason using this wavelength is because, the optical loss at this wavelength is relatively low (lowest fiber loss appeared at the valley between the Reighley scattering and IR absorption, see previous post about basic optics knowledge at: http://ioptic.blogspot.com/2011/08/online-learning-about-optics.html, fiber attenuation: http://ioptic.blogspot.com/2011/08/cut-back-method-for-testing-fibre-loss.html) also, EDFA could amplify light signal at this wavelength.
For fabricating even lower loss optical fibres, few ways could be done, (1) find new materials to replace the silica fibre. Chalcogenide glasses could be one of the candidates. Chalcogenide glasses are transparent at near-infrared and mid-infrared, in this case, chalcogenide fibres are not limited by the IR absorption curve. (2) Guide light using hollow core fibres. (3) Multiple single cores in fibre, maybe. Etc…
University of Southampton and University of Essex in the UK now start up new project ‘Photonics Hyperhighway programme’
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http://gow.epsrc.ac.uk/ViewGrant.aspx?GrantRef=EP/I01196X/1
http://www.orc.soton.ac.uk/PHH/
As38Se62 glass was used for fabricating Microstructured optical fibres (MOFs) by French group (J. Troles).
MOF was fabricated using a casted preform, and the optical loss was demonstrated as low as 0.4 dB/m at 1.55 μm and less than 0.05 dB/m in the mid IR. The MOF cross-section and the coresponding mode profiles are shown in picture.
[6 December 2010 / Vol. 18, No. 25 / OPTICS EXPRESS 26651]
Historically the 1D photonic crystal has been known as the Bragg reflector or mirror, a periodic structure composed of two alternating layers of thickness t=\lambda/4n, where n is the refractive index of the layer and lambda is the free space wavelength for which optimal reflection has been designed.[Y. Yi, http://photonics.mit.edu/Photonic_Crystals.html%5D
A popular example of a photonic crystal device is the photonic crystal fiber, successfully demonstrated by Fink, Joannopoulos et al. at MIT. The ‘Omni guide’ fibre were fabricated using a bilayer (polymer and AsSe glass).[Nature 420, 650-653 (12 December 2002)]
The first demonstration of a photonic crystal waveguide, a planar-processed version of this device, developed by the EMAT group (see in figure). Comprised of a conformal cladded 1D Si/Si3N4photonic crystal; the waveguide core is a defect layer of SiO2.[Y.Yi]
Also, other groups (http://www.4spepro.org/view.php?article=002597-2010-02-05) demonstrated the fabrication of Bragg layer waveguide in polymer.
The future challenge will be demonstration of Bragg-layer fibres in all-glasses.
GeAsSe and AsSe all solid MOFs were fabricated by researcher (Zheng gang Lian)at the University of Nottingham. The fabrication procedures involved glass melting, casting, co-extrusion, stacking and fibre draw.
The paper was published at IEEE PTL. Optical guiding was demonstrated but the optical loss did not mentioned in the paper.
http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=05272506
Researchers at ICB lab in France fabricated low loss As-S suspended core MOFs and demonstrate IR spectral broadening.
The paper published on 1/Mar/2010 on Optics Express. The optical loss of the fibre is ~ 0.35dB/m at 1.55 micron meter wavelength (2.3 micron meter core diameter). The high nonlinear chalcogenide glass MOF can be used for light conversion in the MIR region
Casting method for low loss Chalcogenide MOF
Holey fibre and wagon wheel shape fibre in chalcogenide glasses were produced by Coulombier et al.
Optics 