Planar waveguides configuration

The optical propagation losses in the vacuum evaporated benzylic amide [2] catenane thin films, measured in planar waveguide configuration [47, 48] were found to be PL = 2.8 0.1 dB/cm at A = 1.32 (xm and PL = 4.0 0.1 dB/cm at A = 1.55 (xm, respectively. These values were determined by a two prism method [49]. As for polycrystalline thin films these value are significantly smaller han usually observed. It shows the ability of these molecules to form good optical quality thin films by using these technologically friendly technique. It shows also that the crystallites are very small, tens to a few hundreds of nanometers size. 

A star coupler or optical mixer branches m ports into n ports, which serves to send light to many customers as in data highway or local area networks (LAN). Figure 12 shows a mixer made of manufactured fibers and Fig. 13 utilizes a planar waveguide configuration. 

Fig. 14.4 Basic setup of (a) cylindrical light guides, e.g., fiber optic guides, (b) Planar waveguide configuration...

The calculations in the preceding section have been performed for a simple planar slab waveguide of infinite extent but finite thickness sandwiched between semi-infinite substrate and cover layers. Other waveguide configurations are possible, most notably the cyhndricaUy symmetrical case of a high refractive index rod surrounded by a lower index cladding. This is the fiber-optic configuration used widely in telecommunications. 

In this paper we describe, for the first time, a self-assembly technique that employs alkyl phosphoric acid esters to produce dense, highly ordered monolayers in a tails-up configuration, on a TazOs surface. Tantalum oxide was chosen because of its high refractive index, which renders it ideal for application in a planar-waveguide-based bioaffinity sensor. Upon appropriate m-function-alization, alkanephosphate-based SAMs have the potential to be used as the interface that anchors active sensing elements or as the basis of passive, biomolecule-resistant regions on the sensor surface. 

Figure 22.5 Raman spectra of 75Si02-xHf02- polarization, HH), following a heat treatment (25 - x)fi02 planar waveguides (x = 0, 5,10,15, at 900 °C, for 10 min. The peak marked with an 20, and 25 mol%), obtained in waveguiding asterisk was due to the Si substrate. (After configuration by end coupling (parallel Ref. [19].)...

The successful fabrication of planar waveguides with proper spectroscopic properties and low propagation loss is not the ultimate goal. Demonstration of efficient laser or optical amplification requires a channel waveguide configuration, with lateral and transverse confinement. This supplementary step often generates extra propagation loss. 

PANI was also considered as the cladding in fiber-optic sensors. The sensing configuration benefits from a low detection limit (lower than 10 ppm), and since fabrication is possible with all-polymer materials, the devices are small and low cost. Planar waveguides are also used for gas sensing applications,... 

Linear arrays of optical microresonators evanescently coupled to each other can also be used for optical power transfer (Fig. 6). This type of coupled-resonator optical waveguide (CROW) has recently been proposed (Yariv, 1999) and then demonstrated and studied in a variety of material and geometrical configurations, such as sequences of planar microrings (Poon, 2004), arrays of coupled microspheres (Astratov, 2004), and chains of photonic crystal defect cavities (Olivier, 2001). 

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

On the other hand, deposition-based waveguides usually have a squarelike geometry in a strip, a strip-loaded or a rib configuration (Fig. 6). They are fabricated by depositing several layers onto a planar substrate by means of microelectronic processes, covering and etching them until the final geometry is obtained. 

Fig. 1 Various ring resonator sensor configurations, (a) Microsphere, (b) Silicon-on-insulator planar ring resonator, (c) Slot waveguide ring resonator, (d) Planar disc ring resonator, (e) Glass planar ring array, (f) Microtoroid, (g) Microknot, (h) Opto-fluidic ring resonator (OFRR) and the inset is the SEM image of the OFRR cross-section. Reprinted with permissions from refs [13, 28, 30, 32, 50, 53, 70, 86]...

In MEMS-based optical biosensor systems, similar configurations are used. Light propagates in free space or is guided by optical fibers or planar optical waveguides. In one setup, only the mechanical stmeture (mirror, cantilever, or reaction chamber) is fabricated on wafers. After... 

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