Optical propagation

D. F. G. Gallagher, and T. Felici, Eigemnode expansion methods for optical propagation in photonics - pros and cons, Proc. SPIE 4987, 69-82 (2003). 

V. Superluminal Optical Propagation in Media with Anomalous Dispersion... 

V. SUPERLUMINAL OPTICAL PROPAGATION IN MEDIA WITH ANOMALOUS DISPERSION... 

Optical propagation loss for polymeric electro-optic materials is typically in the order of 1 dB/cm when care is taken to avoid scattering losses associated with processing and poling-induced damage [2, 3, 5, 63, 64, 257]. Lower loss values can be obtained by isotopic replacement of protons with deuterium and with halogens [211, 304, 305]. With effort, electro-optic material losses can be reduced to approximately 0.2 dB/cm for the telecommunication wavelengths of 1.3 and 1.55 microns. 

The phase-matching thickness of a main chain, poled, polyarylamine polymer was also controlled by applying an electric field, tuning the thickness by 25 nm [73]. With the very reasonable optical propagation losses of 2.7 dB cm-1 at 633 nm, this approach should be revisited in the near future [74]. 

To minimize optical propagation caused by light absorption of a harmonic overtone vibration mode, Kim [2] and Ding [3] prepared polyether, (II), and polysulfone, (III), derivatives, respectively, where the majority of hydrogen atoms were replaced by fluorine. 

In all cases the use of an electrode is required, with all possible negative aspects such as charge injection and light absorption. As a consequence, it implies the necessity of using buffer layers, in such applications such as frequency conversion in periodically poled systems [149], in which otherwise it is unnecessary. Moreover, the poling fields are limited due to the microcircuits connected with the point effect. This leads also to unwanted and prohibitory increase of the optical propagation losses. 

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. 

Robertson, M. J., Ritchie, S., and Dayan, R, Semiconductor waveguides analysis of optical propagation in single rib structures and directional couplers, lEE Proc., 132(Pt. J), 336 (1985). 

However, there are several obstacles to their use in practical photonic applications. Single-mode optical waveguides are required for telecommunication systems to allow matching with single-mode fibers. The stability [15] and relatively high optical propagation loss have also been obstacles to utilizing the polymers for photonic applications. 

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