Abstract: An apparatus for aligning a plurality of single-fiber cables, comprises a base, a cover hinged to the base and forming a gap along with the base when closed, and a pair of arms inserted in the gap and movable within the gap, for aligning the single-fiber cables in the same plane. To align single-fiber cables by means of the apparatus, the cables are arranged on the base, one after another. Then, the cover is closed, whereby the cables are located in the gap between the base and the cover. The arms or the pawl members, which are inserted in the gap, are moved, thereby putting the cables together and placing them parallel to one another in the same plane, any cable not forced above so that it rides atop another. The cables, thus aligned, can easily be held by a holder designed for multi-fiber cables.

Abstract: An apparatus for aligning a plurality of single-fiber cables, comprises a base, a cover hinged to the base and forming a gap along with the base when closed, and a pair arms inserted in the gap and movable within the gap, for aligning the single-fiber cables in the same plane. To align single-fiber cables by means of the apparatus, the cables are arranged on the base, one after another. Then, the cover is closed, whereby the cables are located in the gap between the base and the cover. The arms or the pawl members, which are inserted in the gap, are moved, thereby putting the cables together and placing them parallel to one another in the same plane, any cable not forced above so that it rides atop another. The cables, thus aligned, can easily be held by a holder designed for multi-fiber cables.

Abstract: Fusion-splicing polarization maintaining optical fibers includes the steps of: observing a polarization maintaining optical fiber containing stress applying members in a predetermined direction, using a core direct monitoring method to obtain a reference image; aligning the pair of polarization maintaining optical fibers to be fusion-spliced; automatically rotating the fibers while observing them with the core direct monitoring method until the images of the pair coincide with the reference image; and fusion splicing the pair together.

Abstract: .theta.-clamp also serves as a jacket clamp. The clamp comprises a cover mounted on an arm by a hinge and kept closed by a magnet, so that a pusher provided in the cover is urged against a jacketed portion of an optical fiber by a spring. In this state, the fiber is rotated in a .theta. direction by rotating a dial. .theta.-clamp also serves as a jacket clamp. Therefore, 1. The .theta.-clamp can be positioned close to a fiber clamp. For this reason, the optical fiber is not twisted during .theta.-axes alignment, and a follow-up property of rotation of the optical fiber with respect to rotation of the .theta. axis is improved. In addition, the apparatus need not be adjusted so as not to twist the optical fiber. 2. The distance between fiber clamp and .theta.-clamp is shortened. Therefore, when the optical fiber is clamped and moved in the z direction, the jacketed portion is not flexed.