The Boeing Company Phantom Works has
developed three different prototype photovoltaic
concentrator arrays since March 2007. Identified as
Prototype A, B and C, the experimentally proven technical
characteristics of each design are presented. The
concentrator designs utilize a 1 cm2 multi-junction solar
cell assembly in conjunction with SMS non-imaging optical
designs [1, 2] manufactured with low-cost mass-producible
technologies. Prototype A is an on-axis XR optical
concentrator with a 733x geometrical concentration
demonstrating a ± 1.73° acceptance angle and 23.7%
conversion efficiency. Prototype B is an off-axis free-form
XR optical concentrator with a 810x geometrical
concentration demonstrating a ± 1.32° acceptance angle
and 25.3% conversion efficiency. Prototype C is the most
recent off-axis free-form XR optical concentrator with a
801x geometrical concentration and a theoretical ±1.80°
acceptance angle demonstrating a conversion efficiency
greater than 27.0%. Prototype C is also the basis for the
Boeing Proof of Design (POD) module, demonstrating an
acceptance angle of ±1.48° and a conversion efficiency of
29.4% (as of May 8, 2009). Manufacturability has been
paramount during the design process, resulting in high
performance concentrating photovoltaic modules using
production quality components.
Optical windows employed in current and future airborne and ground based optical sensor systems are required to provide long service life under extreme environmental conditions including blowing sand and high speed rain. State of the art sensor systems are employing common aperture windows which must provide optical bandpasses from the TV to the LWIR. Operation Desert Storm experience indicates that current optical coatings provide limited environmental protection which adversely affects window life cycle cost. Most of these production coatings also have limited optical bandpasses (LWIR, MWIR, or TV-NIR). A family of optical coatings has been developed which provide a significant increase in rain and sand impact protection to current optical window materials. These coatings can also be tailored to provide either narrow optical bandwidth (e.g., LWIR) or broadband transmittance (TV- LWIR). They have been applied to a number of standard optical window materials. These coating have successfully completed airborne rain and sand abrasion test with minimal impact on optical window performance. Test results are presented. Low cost service life is anticipated as well as the ability to operate windows in even more taxing environments than currently feasible.
We compare the GaAs and Silica-based approaches for realizing integrated time-shift networks. The performance of a fully functional 2-cm X 2-cm monolithic GaAs circuit is reviewed in detail. In addition, we describe the design of an optoelectronic- switched network that uses Silica-based star-couplers and waveguide arrays.
A monolithic optical time-shift network is described which is designed to steer a dual-band microwave phased array antenna at 2 and 10 GHz. The advantages of using cascade type network architectures to achieve the desired resolution are demonstrated. The implementation of different delay times in this optical time-shifter via bias control of detectors integrated monolithically on a GaAs wafer is described.
A monolithically integrated optoelectronic transmitter is being developed for wideband microwave-modulated links. The transmitter is designed to operate at signal frequencies of several gigahertz. It combines a GaAs/GaAlAs ridge-waveguide laser with a GaAs MESFET driver circuit. The laser has one of its cavity mirrors formed by dry etching so that the die size of the transmitter is not limited to the laser cavity length. The single-stage driver circuit is matched to both the low impedance of the laser and the 50 (Omega) microwave input by the inclusion of reactive components. A single-growth, vertically integrated material structure is used. Potential step-coverage problems that might result from this vertical integration are avoided by the use of air-bridge connections. The submicrometer FET gates are formed by direct-write electron-beam lithography.
Conference Committee Involvement (1)
Energy Harvesting and Storage: Materials, Devices, and Applications
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