Waveguide-Based Devices and Integrated Optochemical Sensors

Waveguide-Based Devices and Integrated Optochemical Sensors 

Optical waveguides generally confine light by means of the total internal reflection (TIR) effect, which is accomplished at the interfaces of a high refractive index dielectric medium (core) surrounded by a lower refractive index medium (cladding and substrate) (Fig. 5) [48,49]. 

Waveguide-based devices can take on different configurations depending on the guiding structures employed cylindrical (optical fibers and capillary waveguides) or planar. 

Standard single-mode fibers are often 10-p.m-thick and multimodal ones 50- and 62.5- im-thick. The latter are the easiest to apply in the optochem-ical sensor field, because they allow a proper light transmission at medium and short distances and can be employed with a great number of commercial optical components. 

The recognition element can be set out at the distal end of the fiber or sidelong between the core and the cladding. 

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