Abstract: A holographic optical element (HOE) device is mounted in wireless optical telecommunication system transceiver. The HOE device includes a developed emulsion material having an interference pattern recorded thereon, sandwiched between a pair of elements, such as a pair of clear glass plates. In operation, the HOE device uses the recorded interference pattern to diffract received light rays towards an optical processing unit of the system receiver. A transmitter unit can be positioned at least in part behind the HOE device. An opening in the emulsion material allows a light signal transmitted from the transmitter unit to be substantially unaffected by the recorded interference pattern. The transceiver can also include a spotting scope and an alignment beacon.

Abstract: A holographic optical element (HOE) device is mounted in wireless optical telecommunication system transceiver. The HOE device includes a developed emulsion material having an interference pattern recorded thereon, sandwiched between a pair of elements, such as a pair of clear glass plates. In operation, the HOE device uses the recorded interference pattern to diffract received light rays towards an optical processing unit of the system receiver. A transmitter unit can be positioned at least in part behind the HOE device. An opening in the emulsion material allows a light signal transmitted from the transmitter unit to be substantially unaffected by the recorded interference pattern. The transceiver can also include a spotting scope and an alignment beacon.

Abstract: A compact, lightweight free-space optical communication system is mounted to a window, such as to a surface of the window. Mounting can be accomplished using glue, vacuum devices, or other fastener devices or fixtures. The optical communication system has features that compensate for window dynamics and other window characteristics, including fast steering solutions for pointing and tracking, and terminal size and weight factors.

Abstract: A voltage measurement instrument such as a digital multimeter is provided with transient overvoltage input protection. Internal walls are integrally molded with the instrument case and disposed in close proximity to the input receptacles and terminals to separate conductive surfaces and provide transient overvoltage barriers. Top and bottom wall portions are fitted together in tongue-and-groove fashion to increase the creepage and clearance path without increasing the linear distance between conductive surfaces. This arrangement also allows the instrument to maintain a low profile.