Abstract: An optical switch includes a plurality of first optical fibers, a plurality of second optical fibers, a first MEMS array, and a second MEMS array. The first MEMS array is optically coupled with the first optical fibers to receive optical signals from the first optical fibers and to direct the optical signals, wherein the first MEMS array defines a first array incidence angle between a normal direction to the first MEMS array and a direction of the received optical signals. The second MEMS array is optically coupled with the first MEMS array to receive the directed optical signals and to re-direct the directed optical signals with the second optical fibers wherein the second MEMS array defines a second array incidence angle between a normal direction to second MEMS array and a direction of the re-directed optical signals. The configuration of the components is provided to provide reduced optical losses.

Abstract: An optical switch having a fiber/lens array and a switching substrate may be properly aligned using one or more grating(s) provided on the switching substrate. The grating(s) may be designed to have a predetermined response when the fiber/lens array and switching substrate are properly aligned. For example, the grating(s) may reflect incident light back into an input fiber, where the back-reflected light may be detected. Accordingly, the position of the switching substrate and/or fiber/lens array may be adjusted until back reflected light having predetermined power is detected.

Abstract: A non-destructive, non-intrusive characterization of angstrom-level roughness characteristics of subsurface interfaces is performed by applying femtosecond light pulses from a laser onto a surface, and analyzing the contents of the reflected pulses. After impinging on the surface being analyzed, the pulses pass through optical filters, which attenuate the fundamental and third harmonic frequencies of the pulses, but keep a substantial portion of the second harmonic. Analysis of the second harmonic signals provides rapid, non-contact, interface-specific characterization of the angstrom-level interfacial microroughness of the subsurface. For semiconductor devices, the second harmonic signals can be used to detect strain, contamination, and trapped charges in the Si/Si(O.sub.2) interface.