title: Double polarization active Y junctions in the L band, based on Ti:LiNbO3 lithium niobate waveguides: polarization and contrast performances.
abstract: Double polarization electro-optic beam combiners based on a Ti:diffusion lithium niobate waveguide have been developed for mid-infrared applications. A monochromatic rejection ratio of up to 33 dB at λ=3.39 μm was obtained, as well as wideband fringes showing low dispersion. In a first part, studying the fringe contrast as a function of waveguide width, we found a compromise among transmission, signal-to-noise ratio, and fringe contrast, depending on the single-mode behavior of the waveguides. We will show that both polarizations are guided, and at least 70% and 90% contrast is achieved, respectively, in TE and TM with a 400 nm wideband light centered at 3.39 μm. After choosing the optimal combiner and designing the electrodes, we studied the electro-optic response of the device, using a monochromatic source and scanning the fringe, by external as well as internal modulation, in order to determine the rejection ratio and the voltage needed to cover half a fringe (V(π)) voltage for both TE and TM polarizations.
authors: Université Joseph Fourier (UJF)-Grenoble 1/CNRS-Institut National des Sciences de l’Univers (INSU), Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), UMR 5274, Grenoble, France. samuel.heidmann@obs.ujf‑grenoble.fr
authors: Samuel
authors: S
authors: Heidmann
authors: Nadège
authors: N
authors: Courjal
authors: Guillermo
authors: G
authors: Martin