Optical propagation loss, measurements

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. 

In this chapter, we review the characterization of sol-gel films by the more common optical spectroscopy methods, but also some more advanced techniques such as optical propagation loss and Z-scan measurements, for nonlinear optical (NLO) characterization, in connection with publkhed research works on inorganic, hybrid, and nanocomposite optical films and planar waveguides. 

This paper summarizes the results of our study of PE and APE waveguides in LiNb03 and EiTa03. We foeused on the optical and structural characterization of PE layers formed on Z-eut substrates. The reffaetive index ehange was measured and the propagation losses were estimated. Raman speetroseopy was used as a method providing direct information about the phonon spectrum. The latter was related to the structure and ehemieal bonds of a given erystalline phase. Sueh information may be useful for eorreet identification of both phase eomposition and the microscopic mechanisms responsible for the observed variation of the properties from phase to phase. 

It would not be an exaggeration to say that the history of plastic optical fibers (POFs) has been a history of the attempts to reduce their transmission loss. The transmission loss limits how far a signal can propagate in the fiber before the optical power becomes too weak to be detected. It measures the amount of light lost between the input and output it is normally expressed in decibels and defined as... 

---