Abstract: According to some embodiments, the optical fiber comprises: (i) a core having a first index of refraction n1; (ii) a cladding surrounding the core and having a second index of refraction n2, such that n1>n2, wherein cladding has at two sets of stress rods extending longitudinally through the length of the optical fiber, wherein the two sets of stress rods have CTE coefficients and/or softening points different from one another and different from that of cladding.

Abstract: A method and an apparatus for making an optical fiber preform comprising the steps of (i) depositing a plurality of rods are deposited into an inner cavity of an apparatus; (ii) depositing particulate glass material in the inner cavity between the rods and the inner wall; and (iii) applying pressure against the particulate glass material to pressurize the particulate glass material against the plurality of rods.

Abstract: An optical system comprising: a light source providing light in 300-700 nm range; and an optical fiber optically coupled to the source; the optical fiber is structured to transmit the light provided by the source and comprises Al doped silica based core with 0 to 1 wt % of Ge and no rare-earth metal(s); and at least one silica based cladding surrounding the core. According to some embodiments the fiber includes: a core having a radius of no more than 2.0 ?m and having a first index of refraction n1 and a relative refractive index delta with respect to the cladding between 0.15 and 1.0%. The Al doped silica core comprises less than 0.5 wt % of Ge and includes no rare-earth metals; and the silica based cladding surrounding the core has a second index of refraction n2, such that n1>n2, the cladding having an outer diameter of 80 ?m or greater.

Abstract: A polarization-maintaining (PM) optical fiber has a pure silica core surrounded by a cladding having a region with randomly arranged voids. Stress members are arranged in the cladding on opposite sides of and in line with the core, and impart birefringence to the PM optical fiber. The PM optical fiber is resistant to aging effects and has a broad single-mode spectral range of 400 nm to 1,600 nm.

Abstract: According to some embodiments, the optical fiber comprises: (i) a core having a first index of refraction n1; (ii) a cladding surrounding the core and having a second index of refraction n2, such that n1>n2, wherein cladding has at two sets of stress rods extending longitudinally through the length of the optical fiber, wherein the two sets of stress rods have CTE coefficients and/or softening points different from one another and different from that of cladding.

Abstract: A method and an apparatus for making an optical fiber preform comprising the steps of (i) depositing a plurality of rods are deposited into an inner cavity of an apparatus; (ii) depositing particulate glass material in the inner cavity between the rods and the inner wall; and (iii) applying pressure against the particulate glass material to pressurize the particulate glass material against the plurality of rods.

Abstract: This invention relates to oil refining, more particularly to a composition of a heavy fuel oil for use in marine power units and boiler plants. The fuel comprises, in percent by weight: an extract from the selective extraction of gas oil—(3-5), heavy catalytic cracking gas oil—(3-10), vacuum gas oil—(5-10), tar or topped residuum—(3-10), straight-run black oil—(10-20), viscosity breaking residue of heavy oil fractions—the rest. The selected combination of the components and their ratio may for example, result in a stable heavy fuel oil having improved viscosity properties. The inclusion of the above components into the fuel composition may also make it possible to expand the production of heavy fuel oils produced.

Abstract: A fiber-optic gyroscope apparatus includes a light source, an optical coupler, a photodetector and an optical circuit device having at least one input, at least two outputs and a birefringent crystal substrate waveguide as a first segment of a Lyot type depolarizer between the input and the outputs. An input fiber of polarization maintaining fiber composition operating as a second segment of a Lyot type depolarizer is located between the optical coupler and the optical circuit device. A sensing coil is coupled to the outputs of the optical circuit device. The input fiber is fixed at approximately 45 degrees to the waveguide, with the input fiber and waveguide cooperating to form a Lyot type depolarizer. Other implementations of the fiber-optic gyroscope apparatus are also disclosed.

Abstract: A partially mirror coated parallelepipedal form is oriented to divide collimated beams along the longitudinal axes from a plurality of diode lasers arranged side-by-side along their transverse axis. The divided partial beams are subsequently recombined and arranged side-by-side along their transverse axis using the same rhomboidal form, where the parallelepipedal form and the polarization state of the collimated diode laser beams are oriented to minimize the insertion loss of the device. The side by side arranged partial beams are further coupled into an optical fiber positioned downstream of the parallelepipedal form to deliver a beam with high optical brightness.

Abstract: The method of making holes in the soil includes driving a capsule into the oil by percussive action and filling the capsule with the soil. Then the driving of the capsule into the soil by percussive action is continued, with the soil passing therethrough. The capsule is then withdrawn from the hole, and the soil that has passed through the capsule is also removed from the hole, whereafter the soil is removed from the capsule itself. The apparatus for making holes, performing the disclosed method, comprises a capsule capable of receiving the soil therein, having an open soil intake end, its opposite end being a partly open one. The capsule incorporates a percussive mechanism.

Abstract: A method of emptying pipes driven into earth in nontrench laying is disclosed, wherein spoil is dug and picked up in the process of movement of a working element by vibratory shock loads, a spoil cushion is simultaneously formed in the pipe for the purpose of taking up reaction loads set up by the movement of the working element, the direction of the vibratory shock loads is reversed after a spoil load is picked up, and the spoil cushion is removed upon completion of the pipe emptying cycles. A device for carrying this method into effect comprises a working element which has a means for retaining the spoil load during withdrawal thereof and is constructed as a barrel, the blind end of which is rigidly connected with a reversible pneumatic hammer, and a chamfer being provided on the open end of the barrel, on the outer surface thereof nearest to the pipe bottom.