Abstract: Aspects of the present disclosure are directed to processing optical signals. As may be implemented in accordance with one or more embodiments, an aperture receives a plurality of optical signals and passes the signals to one or more optical processing stages. Each stage includes a plurality of optical detectors and an optical element that operates with the aperture to provide optical signals from inputs of the stage to at least one of an output of the stage and respective ones of the plurality of optical detectors.

Abstract: Optical fiber waveguides and related approaches are implemented to facilitate communication. As may be implemented in accordance with one or more embodiments, a waveguide has a substrate including a lattice structure having a plurality of lattice regions with a dielectric constant that is different than that of the substrate, a defect in the lattice, and one or more deviations from the lattice. The defect acts with trapped transverse modes (e.g., magnetic and/or electric modes) and facilitates wave propagation along a longitudinal direction while confining the wave transversely. The deviation(s) from the lattice produces additional modes and/or coupling effects.

Abstract: Optical fiber waveguides and related approaches are implemented to facilitate communication. As may be implemented in accordance with one or more embodiments, a waveguide has a substrate including a lattice structure having a plurality of lattice regions with a dielectric constant that is different than that of the substrate, a defect in the lattice, and one or more deviations from the lattice. The defect acts with trapped transverse modes (e.g., magnetic and/or electric modes) and facilitates wave propagation along a longitudinal direction while confining the wave transversely. The deviation(s) from the lattice produces additional modes and/or coupling effects.

Abstract: A detachable face mask assembly for a helmet includes upper and lower mask assemblies removably secured over the helmet face opening with a series of clips. The upper mask assembly includes a first outer component and a first inner component concentrically received therewithin. The inner component may be pivoted upwardly or laterally to provide temporary access to a user's eyes or nose. The lower mask assembly likewise includes a second inner and a second outer component with the inner component pivotable to either side to provide temporary access to a user's mouth or chin. Each of the components are readily and independently detachable from their respective clips upon a predetermined amount of force being applied thereto.