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Current optical telecommunication systems employ dense wavelength division multiplexing (WDM) techniques to increase the data carrying capacity of fiber networks. Dynamic add/drop and filtering processes are crucial for the precise control of individual channels on these networks. Reconfigurable integrated optical devices, such as planar Bragg gratings, can tune the reflection wavelength over several...
Direct-UV-written liquid crystal tunable planar Bragg Gratings exhibit complex wavelength tuning with threshold points and hysteresis. We discuss the role of disclinations in the liquid crystal and whether they may allow faster wavelength tuning.
Direct-UV-written liquid crystal tunable planar Bragg Gratings exhibit complex wavelength tuning with threshold points and hysteresis. We discuss the role of disclinations in the liquid crystal and whether they may allow faster wavelength tuning.
Direct-UV-written liquid crystal tunable planar Bragg gratings exhibit complex wavelength tuning with threshold points and hysteresis. We discuss the role of disclinations in the liquid crystal and whether they may allow faster wavelength tuning.
Nematic liquid crystals (NLC) consist of anisotropic cigar-shaped molecules which, aligned by inter-molecular forces, macroscopically behave as a positive uniaxial with an angle-dependent refractive index for extraordinary eigenwaves. Intense electric fields can therefore induce molecular reorientation towards the field vector through dipolar interaction. Such reorientation in NLC is responsible for...
This study demonstrates Bragg wavelength tuning, with maximum tunability of 114 GHz at 1561.8 nm using patterned ITO glass electrodes with 170 Vpp voltage at 1 kHz. The development of a cascaded architecture of such integrated liquid crystal devices operating at different Bragg wavelengths could pave the way towards true colorless add/drop modules for dynamic dense optical networks.
This work investigated the nonlinear Goos-Hanchen shift (NGS) of nematicons impinging a dielectric interface in the nematic liquid crystals (NLC) planar cell.
We investigate a novel class of vector solitons (VS), two-color spatial solitons in a highly nonlocal and anisotropic Kerr-like medium. While each color experiences a different birefringence and walk-off, the generated nonlocal VS is a self-localized breather with a unique Poynting vector. With reference to the experiments in nematic liquid crystals (NLC), we refer to a reorientational response, adopting...
In this paper, a recently developed micro-templating technology has enabled us to generate cells with spherical mirrors with radius of curvature that spans from 100 nm to 100 mum. This method is based on self-assembly of polyester micro-spheres on a gold substrate followed by electrochemical deposition of gold around them to any desired thickness. Numerical simulations based on a Landau-de Gennes...
Microstructured cells with optical feedback were filled with nematic liquid crystals. The cells were assembled by combining planar ITO substrates and gold-coated hemispherical micro-mirrors. Optical reflection images showed a remarkable change of symmetry in the back-reflected, polarised light when an external voltage was applied. Theoretical modelling of the alignment of the liquid crystals, confined...
Solid-to-liquid and gas-to-liquid phase changes in water and ordered-to-isotropic phase changes in a nematic liquid crystal are detected with an optical sensor. A planar Bragg grating defined purely by refractive index modulation is covered with a water or liquid crystal overcladding and the temperature is controlled to trigger phase changes. Measurement of the Bragg wavelength allows changes of effective...
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