Abstract: Methods for determining optical properties of an optical waveguide fiber using an optical time domain reflectometer (OTDR) are provided. The methods involve the removal of noise from an OTDR trace (signal) by fitting the noise component of the signal and then subtracting the fitted noise from the original signal to produce a noise-reduced signal. Optical properties are more readily determined from the noise-reduced signal than from the original signal. In particular, the noise-reduced signal can be used to determine axial optical properties of long fibers, e.g., fibers having a length of 50 kilometers or more.

Abstract: The present invention relates to a method of measuring spectral attenuation of an optical waveguide fiber using an OTDR. The spectral attenuation curve is generated by analyzing OTDR data taken at three or four wavelengths. There is particular interest in the wavelength range of 1200 nm to 1600 nm, which includes the operating windows about the wavelengths 1310 nm and 1550 nm. A particularly accurate spectral attenuation curve is obtained using OTDR measurements at 1310 nm, 1410 nm, and 1550 nm.

Abstract: Methods for determining optical properties of an optical waveguide fiber using an optical time domain reflectometer (OTDR) are provided. The methods involve the removal of noise from an OTDR trace (signal) by fitting the noise component of the signal and then subtracting the fitted noise from the original signal to produce a noise-reduced signal. Optical properties are more readily determined from the noise-reduced signal than from the original signal. In particular, the noise-reduced signal can be used to determine axial optical properties of long fibers, e.g., fibers having a length of 50 kilometers or more.

Abstract: A method of testing a length section of optical fiber in order to determine whether the angle between an end face of the length section and a plane perpendicular to a longitudinal axis of the length section of optical fiber is within a predetermined range, comprises positioning the length section of optical fiber so that its longitudinal axis substantially coincides with the optical axis of a camera, selecting at least two test regions on the end face of the fiber, adjusting the position of at least one of a camera, a lens and the length section of optical fiber to focus each of the test regions on the sensing surface of the camera, and comparing the adjustments performed in the preceding step for the two test regions respectively.

Abstract: According to the present invention, a new cold working metal process is disclosed for the formation of metal pipe union components, which includes blanks for so called gas meter swivels, which are actually pipe unions components with a slight adaptation. Both male and female components are made by the process. The process cold works a metal elongated hollow open ended blank to deform an unsupported circumferential portion of the blank wall into a predetermined shape. The steps of the process comprise supporting portions of the blank wall exterior and interior in a manner to define a shaping section of the predetermined shape in the area of the unsupported wall portion; applying a compressive load on the blank ends of sufficient force to exceed the compressive yield strength of the metal blank thereby deforming the unsupported wall portions to cause the deforming metal to flow into the shaping section to provide the predetermined shape.