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Arrayed waveguide gratings (AWGs) are key optical components of various new applications in telecommunication, astronomy, medical imaging, and spectroscopy. It is a very powerful integrated light‐dispersion technology with significant flexibility for tailoring its performance to the individual system needs of each application. There are several examples of custom AWG designs in the literature aiming for improved system performance. In this review, an overview of the available methods for improving the bandwidth, spectral resolution, and transmission function shape of AWGs is provided. The working principle as well as the advantages and disadvantages of each method are discussed. [ABSTRACT FROM AUTHOR]

By using integrated optics, it is possible to reduce the size and cost of a bulky optical coherence tomography (OCT) system. One of the OCT components that can be implemented on-chip is the interferometer. In this work, we present the design and characterization of a Mach-Zehnder interferometer consisting of the wavelength-independent splitters and an on-chip reference arm. The Si3N4 was chosen as the material platform as it can provide low losses while keeping the device size small. The device was characterized by using a home-built swept source OCT system. A sensitivity value of 83 dB, an axial resolution of 15.2 µm (in air) and a depth range of 2.5 mm (in air) were all obtained. [ABSTRACT FROM AUTHOR]

Electron and hole charge and discharge dynamics are studied on plasma enhanced chemical vapor deposition grown metal-oxide-silicon germanium nanocrystal flash memory devices. Electron and hole charge and discharge currents are observed to differ significantly and depend on annealing conditions chosen for the formation of nanocrystals. At low annealing temperatures, holes are seen to charge slower but to escape faster than electrons. They discharge slower than electrons when annealing temperatures are raised. The results suggest that discharge currents are dominated by the interface layer acting as a quantum well for holes and by direct tunneling for elec-trons. [ABSTRACT FROM AUTHOR]