Abstract: An all-fiber chirped pulse amplification (CPA) system and method is provided that utilizes a hollow core photonic bandgap fiber as a pulse compressor and a dispersion compensating optical fiber as a pulse stretcher that are matched with respect to both the amount and slope of dispersion to avoid peak power-limiting pulse distortion. The CPA system includes a rare earth ion-doped optical fiber amplifier having an input and an output that amplifies optical pulses having a center wavelength of ?c, a pulse compressing length L1 of hollow core photonic bandgap fiber having a dispersion value D1 and a dispersion slope S1 that varies over a wavelength ? of the pulses that is optically connected to the output of the fiber amplifier and having a k-parameter defined by a ratio of D1 over the slope of the function D1(?) that is larger than about 50, and a pulse stretching length L2 of dispersion compensating optical fiber connected to the input of the fiber amplifier having a dispersion value D2 and dispersion slope S2.

Abstract: An optical fiber, comprising: a core with a first refractive index (n1); a silica based outer cladding surrounding the core, the outer cladding having a refractive index (n), such that the core is substantially surrounded by a gap situated between the core and the outer cladding, the gap containing at least one support structure adjacent to the outer cladding and situated between the outer cladding and the core, wherein the support structure is either hollow or gas filed and is not connected to any other support structure situated within the gap.

Abstract: The present invention is directed to a method and system for providing phase modulated current to a semiconductor laser to control beam wavelength. A first current is received into a gain portion of the semiconductor laser and a second current is received into a DBR portion of the semiconductor laser. The second current is phase modulated based upon a required intensity value. An output beam is generated by the semiconductor laser based upon the received first current and the received second current.

Abstract: An optical waveguide environmental sensor is provided that is capable of detecting a target gas or liquid in the ambient environment in an advantageously short period of time. The waveguide is preferably in the form of an optical fiber having a cladding that contains a photonic band gap structure which in turn envelopes a light conducting, hollow core portion. The cladding further includes at least one elongated side opening that preferably extends the entire length of the fiber and exposes said hollow core portion to the ambient environment, which provides broad and nearly immediate access of the core portion to gases and liquids in the ambient environment, thereby minimizing sensor response time. The ambient gases or liquids filling the hollow core portion and elongated opening function as a ridge and slab, respectively, of an optical ridge waveguide that effectively supports at least one bound optical mode.

Abstract: A method for measuring fundamental mode cutoff wavelength of single polarization fiber comprising: (i) launching pulsed light of at least one wavelength ?i into one end of the single polarization fiber; (ii) measuring backscattered light intensity corresponding to said wavelength to obtain the backscattered light intensity as a function of fiber position, wherein the backscattered light propagates through the same end of the fiber; and (iii) determining at least one cutoff wavelength and the corresponding position within said fiber for the cutoff wavelength, based on a specified threshold light intensity level.

Abstract: A pulsed cascaded Raman laser (10) includes a pulsed light source (102) for generating a pulsed light (104) having an optical spectrum centered at a source wavelength. A non-linear Raman conversion fiber (106) is coupled to the pulsed light source (102). The pulsed light (104) traverses the nonlinear Raman conversion fiber (106) and the source power at the source wavelength is converted to a power output of an output signal (108) having an output wavelength longer than the source wavelength by a cascaded Stimulated Raman Scattering process, such that most of the source power is converted to the power of the last Stokes order in a single pass through the non-linear Raman conversion fiber (106).

Abstract: An exemplary method of making a fuel cell device assemblies includes the steps of: (i) providing a ceramic batch; (ii) extruding the ceramic batch through a die and a mask to form green extrudate that, in cross-section, has at least 10 cells/in2 and wall thickness of 50 mils or less; (iii) cutting the green extrudate to an appropriate length to form a green frame blank; (iv) sintering the green frame blank at a temperature of at least 1200° C., preferably at a temperature of between 1400° C. and 1600° C. for at least one hour to form a ceramic frame with a plurality of parallel channels; (v) inserting at least one fuel cell array into its designated position within the ceramic frame; and (vi) sealing the at least one fuel cell array to the frame.

Abstract: According to one embodiment of the present invention an electrolyte sheet includes a body of varied thickness, the electrolyte sheet having a textured surface with multiple protruding features. The protruding features form an undercut angle with respect to the normal of the electrolyte sheet, the undercut angle being more than 0 degrees and less than 15 degrees.

Abstract: An optical fiber comprising: (i) a silica based passive core having a first index of refraction n1; (ii) a silica based cladding surrounding the core and having a second index of refraction n2, such that n1>n2, said cladding having at least one stress rod and at least one air hole extending longitudinally through the length of said optical fiber; and (iii) wherein said optical fiber supports a single polarization mode or poses polarization maintaining properties within the operating wavelength range.

Abstract: The present invention provides devices and methods for Raman amplification and dispersion compensation. According to one embodiment of the present invention, a dispersion compensating device includes a dispersion compensating fiber having a dispersion more negative than about ?50 ps/nm/km over a wavelength range of about 1555 nm to about 1615 nm; a Raman gain fiber having a dispersion more positive than about ?40 ps/nm/km over a wavelength range of about 1555 nm to about 1615 nm; and a pump source operatively coupled to the dispersion compensating fiber and the Raman gain fiber, the pump source operating at a pump wavelength, wherein the dispersion compensating fiber has a Raman Figure of Merit at the pump wavelength, and wherein the Raman gain fiber has a Raman Figure of Merit at least about equivalent to the Raman Figure of Merit of the dispersion compensating fiber, and wherein the dispersion compensating fiber and the Raman gain fiber are arranged in series between the input and the output of the device.

Abstract: An optical fiber including: (i) a silica based, rare earth doped core having a first index of refraction n1; and (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n1>n2, said cladding having a plurality of stress rods and a plurality of air holes extending longitudinally through the length of said optical fiber; wherein said optical fiber supports a single polarization mode or poses-polarization maintaining properties within the operating wavelength range.

Abstract: A fuel cell and method for manufacturing the fuel cell are described herein. Basically, the fuel cell is formed from an electrode/electrolyte structure including an array of anode electrodes and cathode electrodes disposed on opposing sides of an electrolyte sheet, the anode and cathode electrodes being electrically connected in series, parallel, or a combination thereof by electrical conductors that traverse via holes in the electrolyte sheet. Several different embodiments of electrical conductors which have a specific composition and/or a specific geometry are described herein.

Abstract: A method of fabricating a microstructure for an optical waveguide such as a photonic bandgap fiber is provided. The method includes the steps of assembling a stack of capillary tubes having substantially identical dimensions, fusing and redrawing the stack into a preform having a plurality of parallel holes of equal diameter, selecting a pattern of the holes for etching in order to increase their diameter, and plugging the unselected holes at one end of the preform against the flow of a pressurized etching fluid. Such plugging of the unselected holes is accomplished applying a layer of a gel-like sealant over the end of the preform, and then pushing the sealant into the holes to form sealant plugs in all of the holes. The sealant plugs are then removed from the selected holes by punching the sealant plugs out of the selected holes.

Abstract: An optical waveguide environmental sensor is provided that is capable of detecting a target gas or liquid in the ambient environment in an advantageously short period of time. The waveguide is preferably in the form of an optical fiber having a cladding that contains a photonic band gap structure which in turn envelopes a light conducting, hollow core portion. The cladding further includes at least one elongated side opening that preferably extends the entire length of the fiber and exposes said hollow core portion to the ambient environment, which provides broad and nearly immediate access of the core portion to gases and liquids in the ambient environment, thereby minimizing sensor response time. The ambient gases or liquids filling the hollow core portion and elongated opening function as a ridge and slab, respectively, of an optical ridge waveguide that effectively supports at least one bound optical mode.

Abstract: A solid oxide fuel cell device comprises: (a) zirconia based electrolyte; (b) at least one ectrode situated on the electrolyte; (c) a component situated in close proximity to the electrolyte, the component comprising at least one metal or metal oxide capable, at temperatures of above 625° C., of: (i) migrating to the surface of this component, and (ii) being re-deposited on said at least one electrode; and (d) a protective coating situated on at least one surface of this component. The protective coating substantially prevents the at least one metal or metal oxide from leaving the surface of the component, which is situated under said protective coating. The protective coating is also being substantially impermeable to oxygen.

Abstract: According to one example of the invention an optical fiber comprises: (i) silica based, rare earth doped core having a first index of refraction n1; (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n1>n2; wherein at least one of the core or cladding is doped with Al2O3, such that the ratio of max wt % to min wt % of Al2O3 concentration is less than 2:1.

Abstract: An apparatus and method for routing optical signals in which at least one demultiplexer receives and demultiplexes an incoming wavelength-division-multiplexed optical signal into n individual channels. At least two multiplexers are used for assembling respective multiplexed output signals and are connected by an array of semiconductor optical amplifiers (SOAs), each channel having correspondingly at least two SOAs connecting it respectively to each of the multiplexers. The SOAs are operated in a co-ordinated switching mode to route the corresponding channel selectively to at least one of the multiplexers, and may also contribute gain. A proportionate signal may be split off from each channel and taken to a photodetector to enable the gain of the associated SOAs to be adjusted to equalize or otherwise balance the signal levels.

Abstract: An electrolyte sheet comprises a substantially non-porous body and has at least one stress-relief area on at least a portion of the electrolyte sheet. The stress-relief area has a surface with a plurality of smoothly domed cells.

Abstract: An exemplary fuel cell device assembly is a fuel cell stack assembly comprising: (i) a plurality of fuel cell packets, each of the packets comprising (a) a frame and (b) two planar electrolyte-supported fuel cell arrays, the fuel cell arrays arranged such that anode side of one fuel cell array faces the anode side of another fuel cell array, and the frame in combination with the fuel cell arrays defines a fuel chamber; (ii) a main enclosure enclosing the plurality of fuel cell packets, such that the plurality of packets form a plurality of oxidant channels; (iii) a restrictor plate forming, in conjunction with the fuel cell pockets, a plurality of oxidant channels; (iv) an inlet oxidant plenum manifold connected to one side of the oxidant channels; (v) an outlet oxidant plenum manifold connected to the other side of the oxidant channels; (vi) an inlet fuel manifold connected to one side of each of the fuel chambers; and (vii) an outlet fuel manifold connected to the other side of each of the fuel chambers.

Abstract: An electrolyte sheet comprises a substantially non-porous body and has at least one stress-relief area on at least a portion of the electrolyte sheet. The stress-relief area has a surface with a plurality of folds. The plurality of folds are arranged around and directed longitudinally toward a common central area.