title: Fluorophore-doped xerogel antiresonant reflecting optical waveguides.
abstract: Rhodamine B and Alexa Fluor 430 fluorophores have been used as doping agents for xerogel waveguides defined over an antiresonant (ARROW) filter. This configuration has a significant level of integration, since it merges the waveguide, the light emitter and the filter in a single photonic element. Different technologies have been combined for their implementation, namely soft lithography, standard silicon-based technology and silicon bulk micromachining. The spectral response of 15-mm long waveguides without fluorophore is first analyzed as a function of the waveguide width. Here, it has been observed how the xerogel used has a high transparency in the visible spectra, having only significant absorption at the wavelength where the ARROW filter is in resonance. In a second step, identical waveguides but doped with two different concentrations of Rhodamine B and Alexa Fluor 430 are studied. In addition to the effect of the filter, fluorophore-doped xerogel waveguides show losses close to -2 dB (equivalent to 2 dB of light emission). In addition, it has been observed how an increase of the fluorophore concentration within the xerogel matrix does not provide with a emission increase, but saturation or even a decrease of this magnitude due to self-absorption. Finally, the total losses of the proposed waveguides are analyzed as a function of their width, obtaining losses close to 5 dB for waveguide widths higher than 50 µm.
authors: Institut de Microelectrònica de Barcelona (IMB-CNM-CSIC), Campus UAB 08193 Barcelona, Spain. andreu.llobera@imb-cnm.csic.es
authors: A
authors: A
authors: Llobera
authors: V J
authors: VJ
authors: Cadarso
authors: E
authors: E
authors: Carregal-Romero
authors: J
authors: J
authors: Brugger
authors: C
authors: C
authors: Domínguez
authors: C
authors: C
authors: Fernández-Sánchez