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    Modulation Linearity Characterization of Si Ring Modulators
    (Washington, DC : OSA, 2021) Jo, Youngkwan; Mai, Christian; Lischke, Stefan; Zimmermann, Lars; Choi, Woo-Young
    Modulation linearity of Si ring modulators (RMs) is investigated through the numerical simulation based on the coupled-mode theory and experimental verification. Numerical values of the key parameters needed for the simulation are experimentally extracted. Simulation and measurement results agree well. With these, the influence of input optical wavelength and power on the Si RM linearity are characterized.
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    Remote system for detection of low-levels of methane based on photonic crystal fibres and wavelength modulation spectroscopy
    (New York, NY : Hindawi, 2009) Carvalho, J.P.; Lehmann, H.; Bartelt, H.; Magalhes, F.; Amezcua-Correa, R.; Santos, J.L.; Roosbroeck, J.V.; Arajo, F.M.; Ferreira, L.A.; Knight, J.C.
    In this work we described an optical fibre sensing system for detecting low levels of methane. The properties of hollow-core photonic crystal fibres are explored to have a sensing head with favourable characteristics for gas sensing, particularly in what concerns intrinsic readout sensitivity and gas diffusion time in the sensing structure. The sensor interrogation was performed applying the Wavelength Modulation Spectroscopy technique, and a portable measurement unit was developed with performance suitable for remote detection of low levels of methane. This portable system has the capacity to simultaneously interrogate four remote photonic crystal fibre sensing heads. Copyright © 2009 J. P. Carvalho et al.