Modified superstructure fiber Bragg grating for a filter application

Performance of a modified superstructure fiber Bragg grating is carried out by; simulation using a Matlab and then by optisystem7. Results for these two simulations are compared with an experimental investigation for three special FBGs in addition to a standard one. These four FBGs have one, two, three, and four regions. For each region, Bragg wavelength is increased around 6nm, with constant spacing between every two regions. Laser reflectance (R) and transmittance (T) spectra and their corresponding number of peaks and their bandwidths are observed and analyzed in a constant temperature and strain. Results for this investigation indicate enhancement for the modified FBG to be an effective filter that can be employed for communication as well as sense. Filtering the transmitted signals could be satisfied in a simple and more efficiency than the traditional device.

Case Study on Abnormal Electron-Optical Frequency Mapping Phenomena in Failure Analysis

In recent years, laser reflectance modulation measurements are widely used in failure analysis. Among them, EOFM (Electron-Optical Frequency Mapping) technique is easy to operate and very practical. In this article, some images with abnormal EOFM phenomena and their corresponding defects are showing up, the causes of those abnormal EOFM phenomena are also pointed out. They prove that EOFM function is very effective for discovering open or high-impedance defects on metal trace and pinpointing short-circuit defects. In addition to the two aspects above, there are also some abnormal EOFM phenomena we couldn’t explain perfectly. We studied one of them and proposed two possible causes of the anomaly. After simulation experiment and calculation, it could be basically determined that the abnormal EOFM phenomenon was caused by the substrate noise current.