Abstract: A singlemode optical fiber 700 having very low loss at 1385 nm, and a practical method for making same are disclosed. A core rod 20 is fabricated using vapor axial deposition to have a deposited cladding/core ratio (D/d) that is less than 7.5. The core rod is dehydrated in a chlorine- or fluorine-containing atmosphere at about 1200.degree. C. to reduce the amount of OH present to less than 0.8 parts per billion by weight, and then consolidated in a helium atmosphere at about 1500.degree. C. to convert the porous soot body into a glass. The consolidated core rod is elongated using an oxygen-hydrogen torch that creates a layer of OH ions on the surface of the rod that are largely removed by plasma etching. Finally, the core rod is installed in a glass tube 40 having a suitably low OH content. Thereafter, the tube is collapsed onto the rod to create a preform 60. Conventional methods are employed for drawing an optical fiber from the preform and applying one or more protective coatings 75, 76.

Abstract: A refractory body having reduced optical attenuation, and a method for making same, is disclosed. A refractory body is exposed to a high-temperature oxygen-containing plasma. A drawing force is applied to the body, elongating the body to form a rod of reduced diameter. The source of the plasma is moved in a direction opposite to the applied drawing force, and, preferably, has a reciprocating component of motion to spread the zone of heating. The method is particularly useful in manufacturing optical fiber core rods having low optical attenuation.

Abstract: A bonded optical fiber array (20) includes a parallel coplanar array of longitudinally extending contacting optical fibers (22--22). Each optical fiber is enclosed in inner and outer layers of coating materials and is provided with a color identifier. The inner layer is comprised of a UV curable bonding material having a modulus in the range of about 1 M Pa. For mechanical protection, the outer layer is a UV curable bonding material having a modulus in the range of about 1 GPa. When the optical fibers are disposed in the parallel array, interstices are created between the fibers and between the fibers and an envelope which is spaced no further than about 25 .mu.m at its closest point to each fiber. A UV curable matrix bonding material which has a modulus having a value less than that of the outer coating layer on the fiber and more than that of the inner coating layer fills the interstices, extends to the peripheral line which defines the envelope and bonds together the optical fibers.