Abstract: The invention is an optical labeling/identification system that comprises an optical interrogator, optical label and a programmer. The optical label stores and returns to the interrogator different parts of a wavelength code word. The programmer programs the optical labels with a programming light beam to change the wavelength response of the labels. Interrogation and programming of the labels can be accomplished from a stand off distance without physical contact between the label and the interrogator/programmer. The label may be applied to uneven, wrinkled or discontinuous surfaces.

Abstract: In one embodiment, a fiber optic link includes a combined optical link for transmitting high optical power and wide bandwidth signal through a single optical fiber. In one embodiment, a means is provided for combining a high power optical signal and a low power data signal with wavelength selective directional couplers so as to inhibit the low power data transmitter and the low power data receiver from being overloaded with too much power. In one implementation, a method of using double clad fiber is provided, which includes transmitting an optical data signal at an optical data wavelength along an inner core, the inner core being single mode at the optical data wavelength and simultaneously transmitting an optical power signal at a optical power wavelength through a cladding, the cladding serving as a multimode core for a power optical link at the optical power wavelength.

Abstract: The present invention comprises a method and apparatus to increase the efficiency of photovoltaic conversion of light into electrical power and to achieve operation at higher optical power and therefore higher electrical power. Preferred embodiments increase the efficiency of photovoltaic power conversion of any source of a beam of photons by spatially dividing the beams into a plurality of individual beamlets, each beamlet focusing on an active photovoltaic region. The preferred architecture of the apparatus of the invention comprises spatially separated photovoltaic cells to substantially match the pattern of the spatially separated plurality of beamlets. Preferred embodiments result in a significant reduction in ohmic losses and current shunting, thereby increasing photovoltaic conversion efficiencies.

Abstract: A system and method for focusing electromagnetic energy on a moving target. Generally, the inventive system sends a pilot beam to a target and analyzes a return wavefront to ascertain data with respect to any distortions and other phase and/or amplitude information in the wavefront. This information is then used to pre-distort an output beam by so that it is focused on the target by the intervening distortions. In an illustrative embodiment, the pilot beam is provided by a beacon laser mounted off-axis with respect to the output beam. The reflected wavefront is received through a gimbaled telescope. Energy received by the telescope is detected and processed to ascertain wavefront aberrations therein. This data is used to predistort a deformable mirror to create an output beam which is the phase conjugate of the received wavefront. In a first alternative embodiment, a nonlinear optical phase-conjugate mirror is employed to generate the required wavefront-reversed replica of the received wavefront.

Abstract: A system and method for focusing electromagnetic energy on a moving target. Generally, the inventive system sends a pilot beam to a target and analyzes a return wavefront to ascertain data with respect to any distortions and other phase and/or amplitude information in the wavefront. This information is then used to pre-distort an output beam by so that it is focused on the target by the intervening distortions. In an illustrative embodiment, the pilot beam is provided by a beacon laser mounted off-axis with respect to the output beam. The reflected wavefront is received through a gimbaled telescope. Energy received by the telescope is detected and processed to ascertain wavefront aberrations therein. This data is used to predistort a deformable mirror to create an output beam which is the phase conjugate of the received wavefront. In a first alternative embodiment, a nonlinear optical phase-conjugate mirror is employed to generate the required wavefront-reversed replica of the received wavefront.

Abstract: A Yb-doped fiber laser uses a homogeneously-broadened material. The disclosed laser design is particularly advantageous for operating the fiber laser between 970-980 nm and using this output as a pump for an Er-doped fiber amplifier (EDFA) having an absorption band between 970-990 nm. Using a homogeneously-broadened host glass, for example alumino-germano-silicate or fluoride glass, significantly reduces the inefficiency that can result from the three-level nature of Yb-doped fiber laser transitions that are required for operating it at approximately 976 nm.

Abstract: A Yb-doped cladding pumped fiber laser includes a reflective grating located at each distal end of the laser cavity. Each reflective grating can reflect light propagating inside a fiber core and at a desired wavelength range. A plurality of band-rejecting gratings are disposed between the reflective gratings, whereby the band-rejecting gratings can couple light at an undesired wavelength range and out of the fiber core. When the band-rejecting gratings are in an end-to-end relationship, they are separated by a distance of approximately L whereby L=[(.sigma..sub.e.sup.d +.sigma..sub.a.sup.d)ln 1/T]/[n(.sigma..sub.a.sup.d .sigma..sub.e.sup.u -.sigma..sub.e.sup.d .sigma..sub.a.sup.u)], n is a concentration of ions subject to excitation, .sigma..sub.a.sup.d is an absorption cross section at said desired wavelength range, .sigma..sub.e.sup.u is an emission cross section at said undesired wavelength range, .sigma..sub.e.sup.d is an emission cross section at said desired wavelength range, .sigma..sub.a.sup.

Abstract: Optical apparatus that combines a plurality of separate optical functions into a single monolithic optical element. The the optical element comprises two or three optical functions, such as saturable absorption, retroreflection, and polarization rotation. The optical element comprises a body that is formed in the shape of a right-angle porro prism. The optical element is fabricated from a garnet material that combines the properties of high refractive index (greater than 1.414 to permit total internal reflection at a 45 degree incidence angle), saturable optical absorption (to provide Q-switching), and tolerance to high temperatures (to permit application of anti-reflection coatings). The optical element may be comprised of garnet materials such as yttrium aluminum garnet, gadolinium scandium gallium garnet, or gadolinium scandium aluminum garnet, for example. Doping the garnet materials with tetravalent chromium (Cr.sup.

Abstract: A porous, ceramic member defines both the burner and baffle. Gaseous fuel is supplied under pressure into a chamber and flows through the ceramic member and, in flowing, causes the aspiration of atmospheric air into the flowing gaseous fuel. The air-fuel mixture is ignited a short distance downstream of the chamber and the flame flows through the ceramic member and emerges from the ceramic member within the heat exchanger. The air mixing with the gaseous fuel causes turbulence and mixing of the gas and cools the flame prior to its reaching temperatures associated with the generation of thermal NO.sub.x.

Abstract: The baffle for preventing the recirculation of discharged air into the intake grille of a packaged terminal air conditioner is provided with means for attaching it to the grille structure without fasteners. A plurality of flexible fingers with snap latches on the ends thereof are inserted between a pair of spaced ribs on the grille, with the fingers being flexed inwardly during the insertion process and then flexing outwardly to engage the snap latches with a front edge of the vertical ribs when the baffle is in place.

Abstract: The output of an optical device which involves a stimulated brillouin scattering (SBS) gain medium is enhanced over a range of input beam intensities by providing a gain medium which has a given SBS gain for a given input beam intensity, and modifying the gain medium to reduce its SBS gain coefficient. By lowering the SBS gain coefficient, SBS dominance and suppression of stimulated Raman scattering (SRS) can be mitigated, and the output fidelity of a phase conjugation system with respect to its input can be significantly enhanced. Mechanisms for reducing the SBS gain coefficient include increasing the medium viscosity, thermal conductivity and/or diffusion coefficient, or causing the medium relaxation zone to coincide with the frequency of the phonons involved in the SBS process. Two different media can be mixed together in varying proportions to progressively modify the overall medium SBS gain as the input beam intsnsity is progressively changed.

Abstract: A variable area exhaust nozzle has primary, axially movable flaps tied to an inner unison ring having a box-like cross section and axially movable external flaps tied to an outer unison ring of box-like cross section. The inner and outer rings are concentric, radially aligned, and separated by an engine case. The rings are interconnected by a plurality of pins extending radially from within the outer ring box section to within the inner ring box section through axially extending slots in the case between them. The pins are attached to the rings in a manner preventing relative axial movement therebetween and permitting relative radial movement. When one of the rings is actuated in an axial direction, the other moves axially therewith, the axial actuation force being transmitted by the interconnecting pins. The pins also resist the overturning moment on the rings caused by loads on the nozzle flaps.

Abstract: A gas turbine engine is shown having an annular burner casing with an annular burner therein. A conventional fuel and air supply can be provided. The burner is formed of conventional louver construction at the forward part thereof with the last louver of both the inner and outer burner wall being welded to its upstream louver with a curled forward end being curled to extend away from the upstream louver. This connection is formed on the louvers which restrict the flow through the burner.