Abstract: A routing device for changing the direction of a fiberoptic path from a first axis to a second axis comprising a length of optical fiber having first and second directed fiber portions aligned with the first and second axes, respectively, and having a mid-potion extending through an arc of radius of the order of 2 cm or less; the mid-portion of the fiber having been treated to have a substantially reduced diameter relative to the directed fiber portions. In certain preferred embodiments, the diameter of the mid-portion of the fiber is sufficiently reduced to achieve an air-cladded state. Preferably the routing device includes an outer member for fixing the first and second directed portions relative to one another. The mid-fiber portion is preferably reduced by etching, polishing, or drawing (e.g., differential speed unidirectional drawing). Bent sections of the fiber are thermally annealed forming stress-free bends of minimum bend radius for long term applications.

Abstract: The invention features a fiber optic coupler package including a rigid substrate and at least two side-by-side optical fibers joined in a coupler region. The substrate has a coefficient of thermal expansion substantially matched to that of the fibers. Each fiber extends axially to opposite sides of the coupler region to a primary and secondary regions of fixation, at each side of the coupler region. In the primary region of fixation, each fiber is separately bonded in close proximity to a rigid mounting surface of the substrate using a small amount of adhesive contiguously disposed on opposite sides of the line of tangency formed by the fiber and the mounting surface. The adhesive is distributed to form a pair of substantially identical masses with mirror symmetry relative to a plane defined by the central fiber axis and the line of tangency.

Abstract: Fiber optic couplers formed of at least two single mode optical fibers, at least one of which is an input fiber, are shown, the fibers constructed and arranged in the manner that coupling between the input fiber and the other fibers limits antisymmetric modal energy to substantially less than 50% of the input energy, the coupling region of said coupler being fused and drawn to an extended length sufficient to cause cutoff of the antisymmetric mode energy, whereby the coupler exhibits coupling ratio stability over an extended range of wavelengths and an excess loss of substantially less than 50%. Numerous fiber couplers of various construction, all employing cut-off of the antisymmetric mode to achieve wideband response or wavelength insensitivity are shown along with their method of manufacture.

Abstract: A method and apparatus of polishing the end of an optical fiber that produces relative lateral movement between the end of the fiber and an abrasive surface while changing the angle of attack of the relative movement at a rate greater than about 10,000 arc degrees per second.

Abstract: A means of fabricating wideband 1.times.8 singlemode fiber optic couplers is disclosed. It has been found that a 1.times.7 fiber optic coupler can be fused by twisting six fibers around a central seventh fiber, heating the region on contact among the seven fibers, and drawing until the desired distribution of optical power is achieved among the seven fibers. Both 1.times.6 and 1.times.7 couplers can be made this way depending upon the extent of drawing. Using such a coupler in combination with conventional 1.times.2 and wideband 1.times.2 couplers allows fabrication of 1.times.8 couplers using only two or three separate couplers compared to seven couplers required in coupler tree structures. Further, by taking advantage of selected wavelength response behaviors characteristic of each coupler in the combination, the combination of 1.times.2 and 1.times.7 or 1.times.6 couplers is done in a manner to provide relatively improved coupling uniformity over a bandwidth of .+-.

Abstract: Bends in optical fibers can be miniaturized by reducing the diameter of a section of the fiber in the region where bending is desired to a condition in which the optical properties of the fiber have reduced bend-loss sensitivity. In one aspect of the invention, radii of curvature less than 100 microns (.mu.) and very low optical power loss are achieved. A fiber with such specially reduced diameter may also be twisted about its longitudinal axis to a greater degree than a comparable length of larger diameter fiber. Any optical fiber can be processed by redrawing and/or chemical means to allow such bending or twisting. Bend or twist tolerant regions thus formed may be packaged separately or built integrally into a wide range of fiber optic components, networks, or systems with significant space savings, added performance features and mechanical flexibility.

Abstract: Fiber optic power splitters having a central fiber and a selected number of surrounding fibers spaced periodically around the central fiber and the method of fabricating such splitters are described. For splitters having between three and five surrounding fibers, the central fiber is made to have a reduced diameter relative to the surrounding fibers so that it contacts each of the surrounding fibers and each of the surrounding fibers, likewise, touches each of its neighboring fibers. For splitters having seven or more surrounding fibers, the diameters of the surrounding fibers are reduced relative to the central fiber so that mutual contact is made among the set of equal diameter surrounding fibers and the central fiber. The equation governing the relative diameters of the central and surrounding fibers, and methods of obtaining uniform diameter reduction in an optical fiber are described.

Abstract: An electro-optical converter has at least three optical or electrical ports at least one of which is optical and one of which is electrical. The converter includes an essentially rigid support, a fiber-optic lateral coupler secured to the support including at least two length-wise continuous optical fibers juxtaposed along a portion of their length to provide lateral transfer of optical energy therebetween, and an electro-optical device also secured to the support in close relationship to the coupler. The device has at least one optical port and at least one electrical port. One of the coupler fibers communicates within the converter with the optical port of the electro-optical device, to serve as an internal signal link therebetween. The length of the link between coupler and electro-optical device is of the order of 10 centimeters or less. Protective means associated with the optical fibers, the electro-optical device and the internal link serve to protect the components from outside physical disturbance.

Abstract: A terminator for use with an optical fiber access port structure that supports an optical fiber having an optical end face exposed to communicate with a like end face of another fiber, the terminator comprising a pig-tail-free compact supporting body carrying within itself light-absorbing means and shaped to removably interfit with the access port structure to present the light-absorbing means in light transferring relationship to the exposed end of said optical fiber at the port in manner to absorb incident light from the fiber end face and prevent back-reflection.

Abstract: A fiber optic coupler has at least two optical fibers each having a core with a cladding material disposed thereabout. The fibers, in a limited length coupling region, have the cladding material removed and the core exposed, the thickness of the cladding material increasing is smooth transition from immediately adjacent the exposed core in the limited length coupling region. The fibers in the limited length coupling region are joined by coalescing. In preferred embodiments, in the limited length coupling region, a portion of the core is removed, the core diameter in the coupling region being less than the core diameter in regions adjacent thereto, the outer diameter of the core decreasing in smooth transition from immediately adjacent the cladding material. A method and product of forming these couplers or others with the fibers in crossed relationship are also described.

Abstract: A wideband single-mode fiber optic coupler and method for the fabrication of the same is provided wherein at least two fibers are joined in a fused and tapered coupling region. The taper is asymmetrical in the longitudinal extent about the midpoint of the geometric center of the fused coupling region with the difference between the fiber diameters in that region changing at a varying rate along the length of the region.

Abstract: An optical fiber unit assembly package consists of a protective body having a lid and defining a volume, an entry for an optical fiber cable penetrating the body, at least one optical fiber cable extending through the entry and defining a conduit for an optical fiber cable. An anchor for an optical fiber cable is disposed within the entry as is a clamp for an optical fiber extending through the conduit within the package in a manner to isolate an internal optical fiber unit assembly within the volume from tensile forces applied externally upon the fiber. Secure mounting for optical fiber units within the volume are also provided.

Abstract: A fiber optic coupler and method for forming such coupler is shown in which the substance of the fibers is preselected to have a heat fusing temperature in a range achievable by exterior heating of a shrink sleeve, and the fibers are heat fused together along a limited length region within the shrunken sleeve as a result of heat and inter-fiber pressure applied to the fibers by exterior heating of the shrink sleeve. In preferred embodiments, a filler rod is disposed alongside the optical fibers and pressed thereagainst by the shrink sleeve, the exterior of the rod preferably of fluorocarbon plastic, having an index of refraction lower than the index of refraction of the fibers in the fused region. The interior of the filler rod preferably comprises an elongated heat transfer element having a heat transfer coefficient greatly exceeding the heat transfer coefficient of the fibers.

Abstract: An electro-optical converter has at least three optical or electrical ports at least one of which is optical and one of which is electrical. The converter includes an essentially rigid support, a fiber-optic lateral coupler secured to the support including at least two length-wise continuous optical fibers juxtaposed along a portion of their length to provide lateral transfer of optical energy therebetween, and an electro-optical device also secured to the support in close relationship to the coupler. The device has at least one optical port and at least one electrical port. One of the coupler fibers communicates within the converter with the optical port of the electro-optical device, to serve as an internal signal link therebetween. The length of the link between coupler and electro-optical device is of the order of 10 centimeters or less. Protective means associated with the optical fibers, the electro-optical device and the internal link serve to protect the components from outside physical disturbance.