Abstract: A method for producing a bare fiber taper at a metallized fiber is disclosed and comprises the steps of softening and drawing in an arc of the fiber metallized by sputtering or vapor deposition. The softened metallized fiber thereby constricts and the metallized fiber becomes free of the metallization and, thus, bare over its entire circumference in the arising constriction as a consequence of the influence of the arc. The bare constriction produced in such fashion is parted and a tapering, bare end section thereby arising at one of the two metallized fiber halves produced by the parting can be employed as the bare fiber taper. A fiber taper with lens can be produced by fusing a lens to the bare end section.

Abstract: A method for manufacturing a fiber taper with a refractive lens, said method comprising the steps of placing a fiber in an axial tension of a given amount; locally heating a portion of the fiber under tension to cause softening and the formation of a constriction in the fiber in the area of heating; removing the tension and continuing the heating to raise the temperature to a point at which the viscosity of the heated material is such that the surface tension causes a further constriction and a transverse separation of the fiber at the constriction; continuing the heating to form the desired curvature of the lens on the separated ends; and then after the desired curvature is formed, stopping the heating to enable the ends to cool and solidify.

Abstract: An apparatus for manufacturing constrictions in fibers characterized by a stretching device for stretching the fiber and a heating device for brief local heating of the stretched fiber to a softening temperature. To improve the reliability and reproducibility of the constrictions formed in the fiber, the stretching device includes an arrangement which limits the maximum stretching force applied to the fiber and includes two exactly aligned guide grooves, which are spaced apart with the heating means disposed therebetween, for positioning the fiber during the heating and stretching steps. To produce the exactly aligned guide grooves, the method includes providing a substrate having a rectilinear guide groove, securing the substrate on a support member and subsequently removing a center portion of the substrate to leave a pair of spaced substrate sections having the aligned grooves.

Abstract: An optical polarizer for an optical isolator has a dove prism having a selected geometric shape such that both the incident and emerging beams satisfy the Brewster condition at the respective entrance and exit faces. A further embodiment of the invention consists of the combination of two dove prisms with an intervening multiple layer. The polarizer can be easily adjusted with no reduction in the coupling efficiency with incoming light, can be manufactured inexpensively, and exhibits no parallel offset or astigmatism.