Abstract: The invention provides an optical fiber composition which has a high resistance to aging upon exposure to hydrogen. The inventive optical fiber does not require further treatment steps, such as passivation or hermetic coating, to meet specifications for hydrogen aging. The inventive optical fiber has a core glass composition with a germania doping concentration from 0% to 4% in weight. Decreasing the dopant concentration of germanium increases the resistance of the fiber to hydrogen by reducing the number of germanium defect sites in the core of the fiber. The optical fiber composition is advantageous for rare earth-doped fibers which are particularly sensitive to hydrogen aging.

Abstract: The invention provides an optical fiber composition which has a high resistance to aging upon exposure to hydrogen. The inventive optical fiber does not require further treatment steps, such as passivation or hermetic coating, to meet specifications for hydrogen aging. The inventive optical fiber has a core glass composition with a germania doping concentration from 0% to 4% in weight. Decreasing the dopant concentration of germanium increases the resistance of the fiber to hydrogen by reducing the number of germanium defect sites in the core of the fiber. The optical fiber composition is advantageous for rare earth-doped fibers which are particularly sensitive to hydrogen aging.

Abstract: An optical fiber preform is made by modifying a conventional preform tube having a cladding zone and a core zone, before its thermal collapse normally followed by fiber drawing. The modification is accomplished by depositing, e.g. by MCVD, a thin protective layer of a light-transmissive material, e.g. silica, on the inner surface of the preform tube, over the core zone, before the collapse step. The material of the protective layer has a higher viscosity than the material of the core zone. The protective layer is deposited over the inner (core) zone of the preform tube and its thickness and composition is selected to prevent excessive viscosity drop of the typically alumina-doped core zone during the collapse step. The provision of the protective, viscosity-controlling protective layer is helpful in maintaining good roundness of the collapsed preform tube.

Abstract: A mode-locked solid state laser is disclosed for generating ultrashort optical pulses from a semiconductor type laser. A semiconductor pulse slicer/demultiplexer/modulator with gain amplification is used to modulate and amplify a generated optical beam whether or not the beam is pulsed, continuous wave, q-switched, or modelocked. Alternatively, the semiconductor pulse slicer/demultiplexer/modulator with gain amplification is used to gate a generated optical beam whether or not the beam is pulsed, continuous wave, q-switched, or modelocked. Alternatively, the semiconductor pulse slicer/demultiplexer/modulator with gain amplification is used to demultiplex a generated optical beam whether or not the beam is pulsed, continuous wave, q-switched, or modelocked. The invention uses only semiconductor type materials such as Titanium Saphire, Gallium Arsenide, Aluminum Gallium Arsenide (GaAs/AlGaAs) as both the pulse slicer/demultiplexer/modulator with gain amplification, and the mode-locked laser itself.

Abstract: A squib valve which has an inlet port associated with a pressurized fluid source, an outlet port, flow initiation apparatus for initiating a flow of the pressurized fluid between the inlet port and the outlet port, apparatus for activating the flow initiation apparatus, and flow control apparatus for permitting an increase in the flow at no more than a predetermined maximum rate of increase such that a maximum volumetric flow via the outlet port is reached only after a predetermined minimum period of time has elapsed, thereby reducing the occurrence and magnitude of shock and hammering downstream of the outlet port that would be provided by an uncontrolled outflow of the pressurized fluid.