Active Organic Waveguide Structures for Photonic Devices

• Autores: Luis Felipe Paz Martinez
• Directores de la Tesis: Manuel Caño García (dir. tes.), Xabier Quintana Arregui (dir. tes.)
• Lectura: En la Universidad Politécnica de Madrid ( España ) en 2023
• Idioma: inglés
• Tribunal Calificador de la Tesis: Ricardo Vergaz Benito (presid.), Teona Mirea (secret.), Mohamed Oujja Ayoubi (voc.), Belén Arredondo Conchillo (voc.), Antonio Pérez Serrano (voc.)
• Calificación: Sobresaliente
• Materias:
  • Física
    • Óptica
      • Propiedades ópticas de los sólidos
  • Ciencias tecnológicas
    • Tecnología electrónica
      • Dispositivos láser
    • Tecnología de materiales
    • Tecnología de las telecomunicaciones
• Enlaces
  • Tesis en acceso abierto en: Archivo Digital UPM
• Resumen

  • The present PhD work is aimed at the development of a new research line, within the framework of organic photonics. This Thesis has been developed at CEMDATIC R&D Center, located at Universidad Politécnica de Madrid. During this work, a number of materials have been studied, and many devices have been manufactured and characterized. The obtained results and conclusions will pave the way to the development of novel devices in the field of biosensing. Furthermore, new fabrication techniques have been studied and developed using a great variety of materials, whose performance simplify the routines of manufacturing and the equipment used in well-known and established technologies for micro- and nanofabrication. The main motivation of this work has been driven by the need of simplifying the process of external light coupling into micro or even nano-sized waveguides, which constitutes a fundamental keystone in the photonic integrated circuit technology. The light coupling process is commonly carried out using optical assemblies with micrometric precision, which require electronic control modules in some cases. A suggested solution to this issue can be the incorporation of compatible luminescent materials within the solid matrices that constitute the polymer waveguides themselves. Organic dyes are exceptional candidates for doping polymeric matrices, as they normally show high chemical compatibility with the prepolymers. Owed to the diversity of dyes, whose emission band can be tuned depending on the molecular structure, it would be possible to obtain active matrices emitting at a wide range of wavelengths. Thus, luminescent polymeric structures can be manufactured considering the chemical compatibility of the dyes and the resin molecules under work. The dye not only has to show excellent solubility properties; additionally, it has to maintain its optical properties during and after the curing process of the polymeric material. Along this Thesis, a wide variety of photoresists of different chemical composition have been employed, and organic dye doping has been demonstrated. The obtained luminescent structures, in combination with other light-emitting molecules, cover the whole visible spectrum. Furthermore, if these doped matrices can amplify the light through stimulated emission processes, they may be further used for the design and fabrication of Distributed Feedback (DFB) lasers. Therefore, another goal of this Thesis is the demonstration of light amplification by stimulated emission of photoresists doped with dyes. On the other hand, the ability to generate light within photopolymerizable matrices allows the design and manufacture of sensing devices based on evanescent field excitation principles. Basically, the light that is emitted after exciting externally an active zone can be used to couple a non-active waveguide. These travelling waves can excite targets located on the surface of the waveguide by evanescent field. The light coupling is dependent on the properties of the materials involved in the structure of the devices. In this work, a great variety of cladding and guiding materials have been tested and studied, with the objective to determine the optimal conditions in which the coupling and guiding of light is more efficient. Finally, with the aim of simplifying some of the fabrication techniques commonly used within the framework of micro and nano fabrication of organic structures and devices, we have focused on the development and study of some soft-lithography fabrication techniques, whose processes are based on the use of Poly(methyl methacrylate) (PDMS) molds. The PDMS molds are widely used in traditional Nanoimprint Lithography (NIL) due to its low Young's module and low surface energy, high flexibility, high gas permeability and low cost. In this Thesis, molds of PDMS have been employed to transfer specific patterns from a master to a given substrate, using two main manufacturing techniques known as Solvent- Assisted Micromolding (SAMIM) and Microtransfer Molding (MIMIC). While the first allows the transfer of a pattern (in this case nano-sized gratings) onto a given material in a very efficient way, the latter would allow us to manufacture micro and macro sized structures from the channels or negative patterns generated in the PDMS mold. Therefore, the objective of this Thesis is to investigate new optically active structures combined with efficient manufacturing techniques that can be employed in more complex technologies.