Abstract: The present invention relates to loose-tube optical-fiber cables that are capable of operating in high-temperature environments.

Abstract: In harsh and hazardous environments, the presence of elevated levels of hydrogen gas is an indicator of chemical and/or radiological activity. The present hydrogen-sensing optical fiber provides rapid and reliable hydrogen detection and quantification, irrespective of temperature fluctuations. The hydrogen-sensing optical fiber does not exhibit significant irreversible hydrogen-induced attenuation losses after exposure to a hydrogen-rich atmosphere.

Abstract: The disclosed Plasma Chemical Vapor Deposition (PCVD) process uses the injection of plasma-reactive gas to control deposition oscillation and refractive-index oscillation (e.g., alpha oscillation). This PCVD process, which may employ a modified PCVD apparatus, achieves more uniform glass deposition. This, in turn, results in optical preforms and optical fibers having more uniform optical properties.

Abstract: A method for determining optical properties of an optical fiber including providing optical fibers having varying values of an optical property, measuring values of the optical property of the fibers, selecting one of the fibers as a reference fiber, determining the relative backscatter coefficient of the fibers compared to the reference optical fiber, correlating data obtained in step ii) with data obtained in step iv) to obtain a calibration curve showing a correlation between the Rrel and the values of the optical property of the optical fibers, measuring the Rrel of another optical fiber compared to the reference fiber, and determining a value of the optical property of the another optical fiber based on the calibration curve obtained in step v).

Abstract: The invention relates to an apparatus for performing a plasma chemical vapour deposition process. The apparatus comprises a mainly cylindrical resonator being provided with an outer cylindrical wall enclosing a resonant cavity extending in a circumferential direction around a cylindrical axis. The resonator is further provided with side wall portions bounding the resonant cavity in the cylindrical direction, and with a slit configuration extending in a circumferential direction around the cylindrical axis providing access from the resonant cavity radially inwardly. Further, the slit configuration includes slit sections that are mutually offset in the cylindrical direction.

Abstract: A device for applying electromagnetic microwave radiation in a plasma inside a substrate tube including inner and outer cylindrical walls defining an annular cavity therebetween, the inner wall having a circumferential applicator slit, an elongate microwave guide arranged with a first end in communication with the annular cavity and a second end in communication with a microwave generating means for supplying microwaves to the annular cavity, and means for supplying a cooling gas through the elongate microwave guide to a position near the applicator slit.

Abstract: The invention relates to an apparatus for performing a plasma chemical vapour deposition process. The apparatus comprises a mainly cylindrical resonator being provided with an outer cylindrical wall enclosing a resonant cavity having a substantially rotational symmetric shape with respect to a cylindrical axis. The resonator further includes side wall portions bounding the resonant cavity in opposite cylindrical axis directions. In addition, the apparatus comprises a microwave guide extending through the outer cylindrical wall into the resonant cavity. The length of the resonant cavity in the cylindrical direction varies as a function of the radial distance to the cylindrical axis.

Abstract: A method for manufacturing a primary preform for an optical fibre wherein conditions are created in the reaction zone such that one or more glass layer packages made up of at least two separate glass layers are deposited on the interior of the substrate tube.

Abstract: A method for manufacturing a primary preform for an optical fibre wherein conditions are created in the reaction zone such that one or more glass layer packages made up of at least two separate glass layers are deposited on the interior of the substrate tube. A method for manufacturing a final preform as well as primary preforms, final preforms and optical fibres obtained therewith.

Abstract: A UVLED apparatus and method provide efficient curing of an optical-fiber coating onto a drawn glass fiber. The apparatus and method employ one or more UVLEDs that emit electromagnetic radiation into a curing space. An incompletely cured optical-fiber coating, which is formed upon a glass fiber, absorbs emitted and reflected electromagnetic radiation to effect improved curing.

Abstract: A trench-assisted, multimode optical fiber includes a central core having an alpha refractive index profile with respect to an outer cladding. The optical fiber also includes an inner cladding, a depressed trench, and an outer cladding. The optical fiber achieves reduced bending losses and a high bandwidth.