Paper
9 May 2007 100GHz electrically tunable planar Bragg grating via nematic liquid crystal overlay for reconfigurable WDM networks.
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Abstract
Novel liquid crystal-based integrated optical devices with >140GHz electrical tuning are presented. Initial results with Bragg wavelength tuning covering five 25GHz WDM channel spacing have been achieved with 170V (peak-to-peak) sinusoidal voltages applied across electro-patterned ITO-covered glass electrodes placed 60μm apart. These prototype devices were fabricated using direct UV grating writing, with an evanescent field coupling into a liquid crystal overlay through an etched window. Two distinct threshold conditions are observed, manifesting only during the increase of supply voltage and forming a hysteretic tuning curve. The secondary threshold which takes place at higher voltages has never been reported before. We believe these threshold points are related to the formation and bleaching of disclination lines. Geometric and effective index consideration could not explain the similar tuning behaviour displayed by both TE and TM polarised light.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Faisal Rafiq Mahamd Adikan, James C. Gates, Andriy Dyadyashu, Huw E. Major, Corin B. E. Gawith, Malgosia Kaczmarek, Ian J. G. Sparrow, and Peter G. R. Smith "100GHz electrically tunable planar Bragg grating via nematic liquid crystal overlay for reconfigurable WDM networks.", Proc. SPIE 6587, Liquid Crystals and Applications in Optics, 65870H (9 May 2007); https://doi.org/10.1117/12.722883
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KEYWORDS
Liquid crystals

Waveguides

Electrodes

Fiber Bragg gratings

Glasses

Refractive index

Ultraviolet radiation

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