Review of Optical Fiber Sensor Network Technology Based on White Light Interferometry

Optical fiber sensor networks (OFSNs) provide powerful tools for large-scale buildings or long-distance sensing, and they can realize distributed or quasi-distributed measurement of temperature, strain, and other physical quantities. This article provides some optical fiber sensor network technologies based on the white light interference technology. We discuss the key issues in the fiber white light interference network, including the topology structure of white light interferometric fiber sensor network, the node connection components, and evaluation of the maximum number of sensors in the network. A final comment about further development prospects of fiber sensor network is presented.

"Зародышевые" трещины на поверхности кристалла кремния

The surface (100) of a silicon crystal after cutting the workpiece with a diamond disk and subsequent polishing was studied by the methods of white light interference profilometry and photoluminescence spectroscopy (PL). It was found that it is covered by "grooves". Their length is 10-40 µm, and the depth is quantized. It has values-1, 2.6, 3.6 and 4.5 nm. Four bands (1.63, 1.62, 1.68 and 2.25 eV) were observed in the PL spectra. They arise due to confinement, i.e., an increasing on the band gap width and a violation of momentum of the conservation law in nanocrystals. The sizes of nanocrystals are determined from the energy of the maxima of these bands. They are equal about 2, 2.3, 3 and 4 nm. When cutting silicon or striking it with a striker, fractoluminescence (FL) signals containing 4 maxima were observed. Signals are formed when dislocations break through barriers that occur at intersections.