TY - CHAP A1 - Padilla-Michel, Yazmin A1 - Pulwer, Silvio A1 - Saffari, Pouneh A1 - Ksianzou, Viachaslau A1 - Schrader, Sigurd T1 - On the origin and removal of interference patterns in coated multimode fibres N2 - In this study, we present the experimental investigations on interference patterns, such as those already reported in VIMOS-IFU, and up to now no appropriate explanation has been presented. These interference patterns are produced in multimode fibres coated with acrylate or polyimide, which is the preferred coating material for the fibres used in IFUs. Our experiments show that, under specific conditions, cladding modes interact with the coating and produce interference. Our results show that the conditions at which the fibre is held during data acquisition has an impact in the output spectrum. Altering the positioning conditions of the fibre leads to the changes into the interference pattern, therefore, fibres should be carefully manipulated in order to minimise this potential problem and improve the performance of these instruments. Finally we present a simple way of predicting and modelling this interference produced from the visible to the near infrared spectra. This model can be included in the data reduction pipeline in order to remove the interference patterns. These results should be of interest for the optimisation of the data reduction pipelines of instruments using optical fibres. Considering these results will benefit innovations and developments of high performance fibre systems. KW - instrumentation KW - multimode fibre KW - bending loss KW - fringing KW - interference KW - coating material KW - data reduction Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-15295 SP - 1517 EP - 1527 PB - Society of Photo-Optical Instrumentation Engineers (SPIE) ER - TY - CHAP A1 - Grytsenko, Kostyantyn A1 - Doroshenko, T. A1 - Kolomzarov, Yurii A1 - Prokopets, Vadym M. A1 - Fedoriak, O. A1 - Zelinski, R. A1 - Lytvyn, Oksana A1 - Prescher, Dietrich A1 - Grimm, Bernd A1 - Ksianzou, Viachaslau A1 - Schrader, Sigurd A1 - Tolmachev, O. I. A1 - Slominskii, Yu L. A1 - Kurdiukov, V. A1 - Smirnova, G. T1 - Research on the growth of dye film in vacuum in situ N2 - Organic film deposition in vacuum is fast developing scientific and industrial domain. We developed installation for deposition of organic films equipped with optical spectrometer for measurements in situ. We are developing new dyes aimed for application in waveguide sensor, nonlinear optics and studying film organisation during deposition. Fluorinated azo-dyes and azomethine dyes were synthesized at University of Applied Sciences Wildau and at the Institute of Organic Chemistry, Kyiv. Compounds were evaporated at a pressure of 10-3 Pa using resistive heated crucible. Glass and glass covered with polytetrafluoroethylene (PTFE) film are used as substrates. The films were studied with Polytec and StellarNet spectrometers and an atomic force microscope. Optical spectra of the dye films revealed, that some compounds were decomposed during evaporation. Several kinds of dyes were evaporated and deposited without decomposition. Some deposited films formed H-aggregates and other types of aggregates. AFM images of dye films showed that their morphology depends on the chemical structure of the compounds and on the nature of the substrate on which the film was grown. KW - dye KW - solid KW - film KW - in situ KW - optical spectra KW - vacuum deposition Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-15206 SP - 318 EP - 323 PB - Society of Photo-Optical Instrumentation Engineers (SPIE) ER - TY - CHAP A1 - Meister, Stefan A1 - Al-Saadi, Aws A1 - Franke, Bülent A. A1 - Mahdi, Shaimaa A1 - Kuhlow, Berndt A1 - Voigt, Karsten A1 - Tillack, Bernd A1 - Richter, Harald H. A1 - Zimmermann, Lars A1 - Ksianzou, Viachaslau A1 - Schrader, Sigurd A1 - Eichler, Hans J. T1 - Photonic crystal microcavities in SOI waveguides produced in a CMOS environment N2 - We have investigated microcavities in Silicon-on-Insolator (SOI) waveguides. The rectangular waveguides with 500 nm width are fabricated in the 220 nm silicon device layer. The microcavities are formed by one-dimensional photonic crystals in Fabry-Perot structure directly written in the waveguides. The SOI photonic structures are produced in a CMOS environment using 248 nm DUV lithography, where the waveguides as well as the photonic crystals are created in the same step using a single mask. In order to achieve a desired spectral shape of the filter function capable for several applications, a number of different cavities were investigated, e.g. single cavities of first and higher order as well as multi-cavity filters. The experimental results are compared with simulations of photonic crystal microcavities in strip waveguides. The spectral transmission function of such filters dependent on the design parameters are calculated by an analysis based on Finite-Difference-Time-Domain (FDTD) method. KW - silicon photonics KW - SOI waveguide KW - photonic crystal KW - band-pass filter KW - microcavity KW - FDTD simulation Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-15223 SP - 330 EP - 339 PB - Society of Photo-Optical Instrumentation Engineers (SPIE) ER - TY - CHAP A1 - Wang, Sha A1 - Meister, Stefan A1 - Mahdi, Shaimaa A1 - Franke, Bülent A. A1 - Al-Saadi, Aws A1 - Zimmermann, Lars A1 - Richter, Harald H. A1 - Stolarek, David A1 - Lisinetskii, Viktor A1 - Ksianzou, Viachaslau A1 - Schrader, Sigurd A1 - Eichler, Hans J. T1 - Spontaneous and stimulated Raman scattering in planar silicon waveguides N2 - Raman scattering in planar silicon on insulator (SOI) waveguides with 2 μm width, 220 nm height and 2 cm length is investigated. A cw Nd:YAP laser at 1340.6 nm with 7 GHz FWHM spectral width is used as the pump source. A lensed fiber of 2.5 μm focus diameter is used to couple the pump laser into the waveguide. The coupling efficiency is estimated to be around 10%. Spontaneous Raman scattering is observed with as low as 2.5 mW pump power inside the waveguide. The spontaneous Raman spectrum is measured by an optical spectrum analyzer. The first order Raman peak is measured at around 1441.4 nm corresponding to a Raman shift of 15.6 THz, while the FWHM of Raman spectrum is measured as around 100 GHz. Maximum Raman output of around 90 pW is obtained by around 22 mW pump. The stimulated Raman gain coefficient is estimated as around 56 cm/GW from the relationship between spontaneous Raman output power and pump power. A temperature dependence of Raman frequency shift of about 0.6 GHz/K is measured. The spontaneous anti-Stokes Raman scattering output peak at 1253 nm is also observed with around 35 mW pump. Stimulated Raman amplification measurement is carried out with a SLED white light source as probe signal. With 35 mW pump power, around 0.6 dB gain has been determined with both pump and probe being TE polarized. KW - silicon waveguide KW - Raman Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-15248 SP - 281 EP - 289 PB - Society of Photo-Optical Instrumentation Engineers (SPIE) ER -