Abstract: The end face of an optical fiber assembly consisting of an optical fiber s and a ferrule f is polished to form a conical surface with oblique faces Fp1 and Fp2 such that, central axis Ap of the conical surface makes an inclination of 8.degree. with respect to the optical axis L of the optical fiber s, top Ft of the conical surface coincides with the optical axis L of the optical fiber s, and has a taper angle of 2.degree.. Thereafter, the optical fiber assembly is further polished to form an oblique convex spherical surface at the end face such that, the central axis of the oblique convex spherical surface makes an inclination of 8.degree. with respect to the optical axis L of the optical fiber s. Due to this, insertion loss and light reflected back to the source is stabilized and minimized.

Abstract: End face of a ferrule 100 is polished to form a conical surface 3 such that, central axis Ap of said conical surface 3 makes an inclination of 8.degree. with respect to central axis L of optical fiber insertion hole 4, top 3t of said conical surface 3 coincides with said central axis L and has a taper angle of 2.degree.. Because of this, while polishing an end of a optical fiber inserted and fixed inside said optical fiber insertion hole 4, a well balanced oblique spherical surface can be formed and the non-coincidence of the center of said oblique convex surface with the point where said oblique convex surface intersect with the optical axis of said optical fiber can be prevented.

Abstract: An optical fiber assembly is disclosed, which permits reduction of light reflection, suppression of reflected return light and reduction of connection loss and also facilitates its manufacture. The optical fiber assembly 10 comprises an optical fiber 18 and a ferrule 12 with an end taper and mounted on an end portion of the optical fiber. The end face of the optical fiber 18 and the end face of the ferrule 12 are constituted by a convex spherical surface S1 with the center P0 thereof at a position spaced apart from the center line L0 of the optical fiber 18. The radial line L1 passing through the center P1 of the optical fiber and the center P0 makes an angle .theta.' of 6 to 12 degrees with respect to the center line L0, the radius of curvature is 50 to 70 mm, and the symmetricity angle .DELTA..theta. is 0.1 degree or less.

Abstract: A filter is disclosed which is capable of withstanding repeated use by cleaning. The filter is so constructed that around a frame body is wound a filter wire at a constant slit space of less than 40 with a maximum error of 50%. A method for manufacturing such a filter is also disclosed which comprises winding, on a frame body, a filter wire paired with a spacer wire for keeping the slit space of said filter wire constant in such a manner that each turn is in contact with adjacent turns; and removing the spacer wire alone by chemical or physical means while holding these wires fixed so as to obtain a filter with a smaller slit space error.

Abstract: Disclosed herein is a superconductor covered with a reinforced aluminum matrix, which is obtained by cladding a superconductor with an aluminum matrix reinforced with a very small proportion of alumina dispersed therein and subjecting the clad superconductor to integral forming.

Abstract: Disclosed herein is a superconductor covered with a reinforced aluminum matrix, which is obtained by cladding a superconductor with an aluminum matrix reinforced with a very small proportion of alumina dispersed therein and subjecting the clad superconductor to integral forming by codrawing.