Waveguide structure

BASIC PROPERTIES OF HIGH INDEX-CONTRAST WAVEGUIDING STRUCTURES... 

Figure 1. Schematic illustration of waveguiding structures, a ray-picture b modal intensity distribution obtained with the aid of Maxwell s equation c mode coupling c whispering gallery mode.

A novel technique of producing waveguiding structures by growth of crystals in glass capillaries is presented. This method of crystal growth is simple and is particularly suited to organic materials. 

The advent of integrated optics has highlighted advantages of using waveguiding structures for non-linear interactions and these have been exploited by a number of researchers for optical SHG and mixing. These advantages are ... 

The advantages described above of using waveguiding structures can cancel out if the field overlap integral of the interacting modes is small. This arises since the SHG efficiency is proportional to it. 

As an alternative to planar waveguiding structures we report here the fabrication of crystal cored fibres in which it is possible to maintain uniform guide dimensions over long lengths. These fibres with organic crystal core material having large second order non-linearity could be used for miniaturization of visible laser sources and realization of parametric amplifiers for optical communications. 

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). 

Butler, T. M. Igata, E. Sheard, S. J. Blackie, N., Integrated optical Bragg grating based chemical sensor on a curved input edge waveguide structure, Opt. Lett. 1999, 24, 525 527... 

Fig. 10.1 Binding event between analyte and receptor molecules occurring at the core cover interface of a three layer waveguide structure within the evanescent region of a guided mode. NeS indicates the effective refractive index of the fundamental guided mode...

Fig. 10.3 Total internal reflection in a three layer waveguide structure. n, (i C, F, S) indicates the refractive index of layer i of the waveguide structure, % > nc s dF is the thickness of the core layer...

Fig. 10.4 3D view, cross section, and top view of a channel waveguide structure lVeff c and /Veff s indicate the effective refractive indices of the channel and slab region, respectively... 

In a channel waveguide structure, schematically shown in Fig. 10.4, the light is confined not only in the transverse direction, but also in the lateral one. This confinement is caused by the lateral contrast of the (effective) refractive indices between the channel region, Aleff-c> and the slab, Neff-s> i.e., Neff-c > Neff s- This contrast can be established by the presence of a ridge in the core section, where the... 

Finally, channel waveguide structures can be used to guide the light not only along a straight section, but also in a bent one, e.g., in an S-bend, etc. 

In an immunosensor the core-cover interface of an optical waveguide structure is coated with a chemo-optical transducer receptor layer, which can selectively bind to specific analyte molecules present in the cover medium. The receptor-analyte reaction obeys the law of mass action, which states that the rate of a reaction is proportional to the concentration of the reactants. At equilibrium, the rate of formation of the receptor-analyte complex is equal to the rate of breaking, and the equilibrium constant, K. can be written as... 

Fig. 15.2 Illustration of (a) guided waveguide modes and (b) leaky waveguide modes in a three layered waveguide structure...

First, we consider the three-layer (substrate/waveguide film/cover) structure, assuming that the waveguide structure is left alone without any field incident from the outside. The solutions are obtained by using the solution ansatz iJ> comprising plane waves present in the individual layers ... 

The mode coupling condition for prism coupling (Fig. 15.4a) is similar to the grating condition. For prism coupling the prism often constitute the substrate of the waveguide structure, or the RI of the prism and that of the substrate is matched, and thus the mode s effective index can be calculated from... 

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