Abstract: Techniques are described for reducing splice loss by using an ultra-short bridge fiber to splice together a first fiber and a second fiber having different modefield diameters. The ultra-short bridge fiber has an intermediate modefield diameter between the modefield diameters of the first and second fibers. In one described technique, a first end of the ultra-short bridge fiber is spliced to a lead end of the first fiber at a first splice point. The bridge fiber is then cleaved at a predetermined distance away from the first splice point. A lead end of the second fiber is then spliced to cleaved end of the bridge fiber at a second splice point. A single protective splint is then installed that covers the bridge fiber and the first and second splice points. Further described is an optical fiber transmission line including an ultra-short bridge fiber.

Abstract: Systems and techniques are described for monitoring a pre-splice heat treatment of an optical fiber. In one described technique, a lead end of a first fiber is prepared for splicing. The lead of the fiber is then loaded into a heat treatment station. While heating the lead fiber end, an optical time domain reflectometer is used to measure reflected backscatter loss from the lead fiber end. The lead fiber continues to be heated end until the measured reflected backscatter loss from the lead fiber end reaches a predetermined level. At that point, the heat treatment is discontinued.

Abstract: Systems and techniques are described for improving reproducibility in a pre-splice heat treatment. A heat treatment station is described for applying a pre-splice beat treatment to a lead end of a first optical fiber having a first modefield diameter. The heat treatment station comprises a base, and a fiber clamp for holding the first optical fiber such that a length of the lead end of the first optical fiber is positioned over a heat source mounted to the base. The heat source causes a controlled expansion of the first fiber modefield at the first fiber lead end to form an internal bridge. The heat treatment station further includes position adjustment means for adjusting the length of the first fiber lead end that is exposed to the heat source.

Abstract: Systems and techniques are described for improving reproducibility in a pre-splice heat treatment. A heat treatment station is described for applying a pre-splice heat treatment to a lead end of a first optical fiber having a first modefield diameter. The heat treatment station comprises a base, and a fiber clamp for holding the first optical fiber such that a length of the lead end of the first optical fiber is positioned over a heat source mounted to the base. The heat source causes a controlled expansion of the first fiber modefield at the first fiber lead end to form an internal bridge. The heat treatment station further includes position adjustment means for adjusting the length of the first fiber lead end that is exposed to the heat source.

Abstract: Systems and techniques are described for monitoring a pre-splice heat treatment of an optical fiber. In one described technique, a lead end of a first fiber is prepared for splicing. The lead of the fiber is then loaded into a heat treatment station. While heating the lead fiber end, an optical time domain reflectometer is used to measure reflected backscatter loss from the lead fiber end. The lead fiber continues to be heated end until the measured reflected backscatter loss from the lead fiber end reaches a predetermined level. At that point, the heat treatment is discontinued.

Abstract: Techniques are described for reducing splice loss by using an ultra-short bridge fiber to splice together a first fiber and a second fiber having different modefield diameters. The ultra-short bridge fiber has an intermediate modefield diameter between the modefield diameters of the first and second fibers. In one described technique, a first end of the ultra-short bridge fiber is spliced to a lead end of the first fiber at a first splice point. The bridge fiber is then cleaved at a predetermined distance away from the first splice point. A lead end of the second fiber is then spliced to cleaved end of the bridge fiber at a second splice point. A single protective splint is then installed that covers the bridge fiber and the first and second splice points. Further described is an optical fiber transmission line including an ultra-short bridge fiber.

Abstract: Optical fiber drawn from preforms including sol-gel-derived glass is found to contain small refractory particles of the order of a micron in size. These particles initiate fiber breaks with the result that fiber may not meet proof-test tensile strength requirements. An effective separation method relies upon density and/or size difference from suspended sol particles for separation in the ungelled sol. A preferred separation procedure is centrifugation.