U.S. Philips Corporation

Adrianus P Severijns

Frans A Staas

Petrus J Severin

Cornelus Hm Van Bommel

Jacobus J Ruigrok

Cornelis M Jochem

Jacobus Bernardus Giesbers

Jacobus Stoffels

Franciscus M Oostvogels

Franciscus W Dirne

Franciscus Henricus Aarts

Charles C Meulemans

Willem Van Haeringen

Johannes A Steenbakkers

A method of manufacturing one or more magnetic heads starts from a substrate (11) on which a first magnetic layer (13) is provided. A recess (15) is formed in this layer at the location of a transducing gap to be formed, after which a gap layer (19) is provided on a bounding wall (17) of the recess. Subsequently, the recess is filled with a second magnetic layer (23) and a counterblock (31) is provided on the layers after surface-polishing. Finally, a winding aperture is provided.

Method of manufacturing a magnetic head

A passive fiber optic component, in which two or more fibers are each bared at one end by removal of the outer coating of the fiber. The bare portions of the fibers are etched to produce cylindrical end portion which adjoins a conical portion. Subsequently, the fibers are arranged with their etched portions in a capillary tube which is sealed at one end. The tube is then evacuated and is fused with the etched portions of the fibers to form a solid rod with a rotationally symmetric distribution of the end portions of the fibers. The fibers are etched to such a diameter that after fusion of the fibers with the tube, the fused fiber ends have a circular cross-section substantially equal to the cross-section of a single fiber core. An end face is formed on the rod by cleaving or by grinding, and by polishing to obtain a fused fiber head. The fiber head forms a fiber optic component itself, or forms a basic element for a great number of fiber optic components such as splitters and couplers.

Passive fiber-optic component

The invention relates to an irradiation device which is employed in particular in an arrangement for cladding a filamentary body 5, and to a method of cladding such a filamentary body 5, which irradiation device comprises a light source 1 and at least one optical conductor 4 which is provided with a light-entrance window at a first end and a light-exit window at a second end, the light-entrance window being directed to the light source. A cylinder lens 6 is positioned between each light-exit window and the location of the object to be irradiated during operation of the device. Preferably, the first end of the optical conductor 4 is sealed into the wall of a lamp envelope and the cylinder lenses are provided in the wall of a mainly cylindrical body 7 through which a filamentary body 5 which is to be clad can be led.

Irradiation device, arrangement for and method of cladding a filamentary

The irradiation device comprises a short arc discharge lamp, in which a pair of electrodes are arranged, between which a discharge path extends. An optical conductor is sealed with its first end into the wall of the lamp vessel in such a manner that its light entrance window is arranged laterally of the discharge path and is directed to the discharge path.

Irradiation device comprising a short arc discharge lamp

A predetermined number of optical fibre parts (27) is provided on a rectangular frame (1), the fibre parts extending parallel to each other along a straight line between two opposite first sides (3) of the frame. These first sides (3) comprise comb-shaped fibre guides (5) with teeth (13), between which the fibre parts (27) are guided so that the fibre guides determine a first relative distance between the fibre parts. The first sides (3) are pivotably connected to the two second sides (7) of the frame (1), which is then deformed to a parallelogram until the portions of the fibre parts (27) located inside the frame have a predetermined second relative distance. A permanent connection between the fibre parts (27) is established so that a ribbon of fibre parts is obtained. A number of such ribbons can be stacked with the interposition of strip-shaped spacers (29) to form a bundle.

Method of manufacturing a bundle of optical fiber parts

To a carrier (1, 1') there is cemented a bar of a material (3, 3'), for example glass or a ceramic material, which is subsequently divided, using cuts (7, 7') which extend transversely of its longitudinal direction, into a number of slices (9, 9') which are separately cemented to the carrier. Each slice (9, 9') is provided with a groove (13, 13') which extends parallel to the cuts (7, 7'). The grooves (13, 13') are curved and have a center of curvature which is situated at the side of the bar (3, 3') which faces the carrier (1, 1'). In the grooves (13, 13') there are secured optical fibres (19, 19') which follow the curvature of the groove, after which a side portion of the fibres which is situated furthest from the carrier (1, 1') is ground off. A flat ground face (21, 21') is thus formed one each fibre (19, 19'). Such ground fibres (19, 19') are arranged so that their ground faces contact one another in order to form directional couplers, after which the slices (9, 9') are detached from the carrier (1, 1').

Method of manufacturing a plurality of optical components

A method of manufacturing a passive fiber optic component, in which two or more fibers are each bared at one end by removal of the outer coating of the fiber the bare portions of the fibers are etched to produce a cylindrical end portion which adjoins a conical portion. Subsequently, the fibers (1) are arranged with their etched portions in a capillary tube which is sealed at one end. The tube is then evacuated and is fused with the etched portions of the fibers to form a solid rod with a rotationally symmetric distribution of the end portions of the fibers. The fibers are etched to such a diameter that after fusion of the fibers with the tube, the fused fibers ends have a circular cross-section substantially equal to the cross-section of a single fiber core. An end face is formed on the rod by cleaving or by grinding, and by polishing to obtain a fused fiber head. The fiber head forms a fiber-optic component itself, or forms a basic element for a great number of fiber-optic components such as splitters and couplers.

Method of manufacturing a passive fiber optic component

A .sup.3 He-.sup.4 He dilution refrigerator comprises an upper mixing chamber for mixing liquid concentrated .sup.3 He and superfluid .sup.4 He, and a lower segregating chamber for separating concentrated .sup.3 He and superfluid .sup.4 He. An auxiliary chamber is situated between the mixing chamber and the segregating chamber. A connecting duct extends between the segregating chamber and the auxiliary chamber. The upper part of the auxiliary chamber communicates with the upper part of the mixing chamber for flow of concentrated .sup.3 He into the latter; and the lower part of the auxiliary chamber communicates with the lower part of the mixing chamber for flow of dilute .sup.3 He to the lower part of the auxiliary chamber.

.sup.3 He-.sup.4 He Dilution refrigerator

.sup.3 He-.sup.4 He refrigerator in which superfluid .sup.4 He is circulated by a thermomechanical pumping device which is based on the fountain pump effect and which is constructed from several series-arranged fountain pumps.

.sup.3 He-.sup.4 He refrigerator

A superleak in which a heat exchanger having a superleak structure is included in order to drastically reduce heat leak in the flow direction during operation.

Superleak

A .sup.3 He-.sup.4 He dilution refrigerator is provided with two interconnected mixing chambers arranged at different levels. One end of a superleak opens into concentrated .sup.3 He contained in the upper mixing chamber, while the other end opens into a portion of the apparatus containing dilute .sup.3 He for the supply of superfluid .sup.4 He, via the superleak, to the upper mixing chamber under the influence of the osmotic differential pressure prevailing across the superleak.

A .sup.3 He-.sup.4 He dilution refrigerator provided with a variable-flow restriction member in the supply duct for flowing the condensed helium into the mixing chamber, such member being controlled by the flow of condensed helium and having a flat flow passage curve.

.sup.3 He-.sup.4 He dilution refrigerating machine

A refrigerator operable with an evaporation chamber and superfluid .sup.4 He II for temperatures below the .lambda.-point of helium, and means for preventing the .sup.4 He II from creeping upward out of the evaporation chamber.

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Eindhoven, Netherlands

Adrianus P Severijns