Abstract: A holder for annealing a fiber optic coil uses a silica ring on a silica substrate, or silica tubular coil, either of which may be directly incorporated into a coil subassembly for a Faraday-effect current sensor. The ring may be formed in a silica plate by sandblasting or grinding, or formed separately and adhered to the plate. In the tubular holder embodiment, silica tubes and sleeves are used to protect fusion splices between the ends of the fiber coil and polarizing fibers. Use of silica for most of the subassembly components matches the coefficients of thermal expansion of the subassembly to that of the fiber coil, and also allows the coil to be annealed at extremely high temperatures. Annealing yields fiber coils of lowered birefringence, particularly when used with spun fibers. Ferrules are used to adjust the angular orientation of the fibers with respect to their planes of polarization.

Abstract: A single-mode, single-polarization optical fiber ("PZ fiber") can have a large single-polarization wavelength bandwidth when .eta. (as herein defined) for one symmetry axis is positive when calculated from the refractive index profile determined with one of two orthogonal orientations of polarized light and is negative when calculated from the refractive index profile determined with the other orientation, and for each other symmetry axis of the novel optical fiber .eta. is positive for both orientations of plane polarized light. Preferably the absolute values for .eta. when positive and .eta. when negative are about equal for said one symmetry axis. A preferred PZ fiber can be formed by depositing siliceous layers onto the interior surface of a hollow substrate tube of quartz to provide a preform. After forming two parallel flat faces in its outer surface, the preform is pulled to form a PZ fiber having an ellipitcal stress-applying region.

Abstract: A single-mode, polarization-maintaining optical fiber has both excellent signal attenuation and resistance to adverse bending effects because (1) its cladding and any portion of the jacket that is within five times the radius of the mode-field in its core have a substantially uniform index of refraction that is at least 0.005 less than that of pure silica, and (2) the index of refraction of the core is at least as great as, but preferably not substantially greater than, that of pure silica. Preferably, the stress-applying region of the fiber is elliptical, and the jacket is pure silica.

Abstract: A connector for an optical fiber cable is disclosed wherein strain relief features are provided for minimizing strain applied either to the external jacket of the cable or to the fiber such as during connecting operations is prevented from being coupled to the optical fiber. The connector thus includes strain relief members for securely anchoring the outer jacket of the cable and for anchoring strain relief fibers contained within the cable. Also, a resilient member is provided for allowing limited rearward movement of a member within which the optical fiber is anchored such as may occur during connection.