Thin film optical waveguide

Several techniques can be employed to couple an optical beam propagating in free space into a thin-film optical waveguide. Grating coupling and prism coupling (Fig. 15.4) are briefly outlined here, since these methods are applied in actual reverse waveguide and MCLW configurations, respectively. 

Pale yellow cerium dioxide (ceria, ceric oxide) has the fluorite structure and is used in catalysis" ", solid oxide fuel cells (SOFC)", thin film optical waveguides" , reversible oxygen storage materials for automobile catalysts" and for doping copper oxide superconductors". The diverse cerium enolate precursors and deposition methods used in the formation of cerium oxide thin films are summarized in Table 6, whereby the most common precursor for ceria is Ce(thd)4. 

Schlotter, N. E., and Rabolt, J. F. Raman Spectroscopy in Polymeric Thin Film Optical Waveguides. 1. Polarized Measurements and Orientational Effects in Two-Dimensional Films. J. Phys. Chem. 88 2062-2067 (1984)... 

NLO or SHG effects. In a related application, LB films have been used as thin film optical waveguides (2). 

Wang X., Xu L., Li D., Liu L., Wang W. Themio-optic properties of sol-gel-fabricated organic-inorganic hybrid waveguides. J. Appl. Phys. 2003 94 4228-4230 Weber H.P., Dunn F.A., Leibolt W.N. Loss measurements in thin-film optical waveguides. Appl. Opt. 1973 12 755-757... 

Weidman, X W., Kwoch, E. W., Bianconi, P. A., and Hornak, L. A., Synthesis and applications of polysilyne thin film optical waveguide media, in Polymers for Lightwave and Integrated Optics, Hornak, L. A., Ed., Mercel Dekker, New York, 1992, Chap. 7. 

Hornak, L. A. and Weidman, X. W., Propagation loss of index imaged poly(cyclohexylsilyne) thin film optical waveguides, Appl. Phys. Lett., 62, 913, 1993. 

While planar optical sensors exist in various forms, the focus of this chapter has been on planar waveguide-based platforms that employ evanescent wave effects as the basis for sensing. The advantages of evanescent wave interrogation of thin film optical sensors have been discussed for both optical absorption and fluorescence-based sensors. These include the ability to increase device sensitivity without adversely affecting response time in the case of absorption-based platforms and the surface-specific excitation of fluorescence for optical biosensors, the latter being made possible by the tuneable nature of the evanescent field penetration depth. 

In this paper we report functional waveguides exhibiting SHG in tapered thickness 2-methy1-4-nitroani1ine(MNA) thin film crystal waveguide, and all optical bistabi1ity,in tensity dependent optical modulation in vacuum evaporated polydiacetylene(PDA) thin film waveguides. 

Tomonari, M., Ookubo, N. and Takada, T. (1997). Chem. Phys. Lett. 266, 488 IWieg, R. J. and Dirk, C. W. (1996). Design, properties and applications of nonlinear optical chromophores. In Science and Technology of Organic Thin Films for Waveguiding Nonlinear Optics (eds F. Kajzar and J. Swalen), Gordon and Breach, Amsterdam, p. 45... 

Kayzar, F. Swalen, J.D. (1996) Organic Thin Films for Waveguiding Nonlinear Optics, Amsterdam, Gordon and Breach. 

Swalen J, Kajzar F (1996) Organic thin films for waveguiding nonlinear optics science and technology. In Kajzar F, Swalen J (eds) Gordon 8c Breach, Amsterdam, p 1... 

Device Fabrication The relative ease of control of the sol-gel process renders it suitable for device fabrication such as thin films, optical fibers, and optical waveguides (both channel and planar). 

Fabrication of Passive and Active Tellurite Thin Films and Waveguides for Integrated Optics... 

This chapter reviews the fabrication and properties oftellurite planar thin films and waveguides for integrated optics. The basic properties of tellurite are summarized, and then the various techniques used for thin-film and waveguide fabrication are detailed. The latest achievements in rare earth-doped, especially erbium-doped, tellurite waveguide devices are also discussed. 

Vu, K. T., Madden, S. J., and Luther-Davies, B.,"Low loss stoichiometric Te02 thin films and waveguides,"in 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009, Baltimore, MD, United states, [IEEE Computer Society, 2009). 

These materials are compatible with semiconductor technology. Low-oost thin films or waveguiding structures of polymers can be fabricated easily by fomiliar spincoating processes which meet the requirements of integrated nonlinear optics. Polymers and. in particular, side-chain polymers, liquid crystalline or amorphous ones, offer a high potential for molecular engioeering. 

In addition, the integration of modem optical technology and electrochemical techniques for sensing applications appears to be a powerful new approach. A new type of optoelectrochemical sensor for chlorine, based on an electrochromic thin-film sensing layer placed on top of a planar waveguide, has demonstrated the applicability of this combined approach. 

Piraud C., Mwarania E., Wylangowski G., Wilkinson J., O Dwyer K., Schiffrin J., An optoelectrochemical thin-film chlorine sensor employing evanescent fields on planar optical waveguides, Anal. Chem. 1992 64 651. 

In addition to absolute pressure measurements, pressure sensors can be used to determine flow rates when combined with a well-defined pressure drop over a microfluidic channel. Integration of optical waveguide structures provides opportunities for monitoring of segmented gas-liquid or liquid-liquid flows in multichannel microreactors for multiphase reactions, including channels inside the device not accessible by conventional microscopy imaging (Fig. 2c) (de Mas et al. 2005). Temperature sensors are readily incorporated in the form of thin film resistors or simply by attaching thin thermocouples (Losey et al. 2001). 

In many practical situations, the waveguiding layer consists of an optically dense media formed as a thin film with a thickness dp and refractive index nP. This film is usually applied on a solid substrate (typically glass) with refractive index ns less than the RI of the film. The macroscopically thick substrate creates a mechanically stable foundation for the above film, which has a thickness typically in the submicron range. In this case, the light can travel by TIR inside the film, in a zigzag manner (see Fig. 15.2a), creating the evanescent wave both in the aqueous cover solution with refractive index nc and in the substrate10. 

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