Observatorio de I+D+i UPM

Memorias de investigación
Communications at congresses:
Manufacturing arbitrarily-shaped active waveguides with liquid crystal cladding
Research Areas
  • Optics, electromagnetism,
  • Device photon transmitters of light
Many photonic devices are based on waveguides (WG) whose optical properties can be externally modified. These active WGs are usually obtained with electrooptic materials in either the propagating film (core) or the substrate (cladding). In the second case, the WG tunability is based on the interaction of the active material with the evanescent field of the propagating beam.Liquid crystals (LCs) are an excellent choice as electrooptic active materials since they feature high birefringence, low switching voltage, and relatively simple manufacturing. In this work, we have explored alternative ways to prepare WGs of arbitrary shapes avoiding photolithographic steps. To do this, we have employed a UV laser unit (Spectra Physics)attached to an xyzCNC system mounted on an optical bench. The laser power is 300mW, the spot size can be reduced slightly below 1 µm, and the electromechanicalpositioning is well below that number.Different photoresinshave been evaluated for curing time and uniformity; the results have been compared to equivalent WGs realized by standard photolithographic procedures. Best results have been obtained with several kinds of NOA adhesives (Norland Products Inc.) and SU8 (Microchem). NOA81 optical adhesive has been employed by several groups for the preparation ofmicrochannels [1] and microfluidic systems[2]. In our case, several NOAs having different refractive indices have been tested in order to optimize light coupling and guiding. The adhesive is spinnedonto a substrate, and a number of segmented WGs are written with the laser system. The laser power is attenuated 20 dB. Then the laser spot is swept a number of times (from 1 to 900) on every segment. It has been found that, for example, the optimum number of sweeps for NOA81 is 30-70 times (center of the figure) under these conditions. The WG dimensions obtained with this procedure are about 7 µm high and 12 µm wide.
16TH Topical meeting on the Optics of Liquid Crystals 2015
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16TH Topical meeting on the Optics of Liquid Crystals 2015
  • Autor: Manuel Caño Garcia (UPM)
  • Autor: Tianyi Zuo (Beihang University)
  • Autor: Rodrigo Delgado (UPM)
  • Autor: Morten Andreas Geday (UPM)
  • Autor: Patxi Xabier Quintana Arregui (UPM)
  • Autor: Jose Manuel Oton Sanchez (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Grupo de Fotónica Aplicada
  • Centro o Instituto I+D+i: Centro de Materiales y Dispositivos Avanzados para Tecnologías de Información y Comunicaciones
  • Departamento: Tecnología Fotónica y Bioingeniería
S2i 2020 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
Cofinanciación del MINECO en el marco del Programa INNCIDE 2011 (OTR-2011-0236)
Cofinanciación del MINECO en el marco del Programa INNPACTO (IPT-020000-2010-22)