Abstract: A method for measuring the secondary path intensity of an optical unit, such as an optical amplifier, is provided. The method includes applying a pulse of light to a first end of the unit and detecting the light exiting from the second end of the unit. The exiting light is analyzed to determine a primary pulse intensity and a secondary pulse intensity which preferably includes the effects of Rayleigh backscattering (RBS). The ratio of the secondary pulse intensity to the primary pulse intensity provides an accurate measure of the unit's secondary path intensity.

Abstract: A system for controlling the drawing of a hermetically-coated optical waveguide fiber from a preform is provided in which two measurements of fiber diameter are made and combined into an overall control signal. The first measurement is made on bare fiber in the region of the preform's root using an interference technique. The second measurement is made after the hermetic coating has been applied using a shadow technique. The first measurement provides high speed, high accuracy data needed for process control and defect detection. It is, however, subject to error due to fluctuations in the root with tractor speed. The second measurement reduces the effects of such error on the overall control signal.

Abstract: The invention comprises (a) a divider (D) by 2 of the optical power received at one input (E.sub.1, E.sub.2) and (b) two groups of single mode waveguides coplanar to the divider and symmetrical relative to the axis of symmetry (Z) of the divider (D), each group being composed of waveguide sections connected in tree and branch fashion by Y junctions (J.sub.ii) between one input junction (J.sub.11, J.sub.12) connected to one of the outputs of the divider and N sections of waveguide difining N outputs (S.sub.1 to S.sub.16) of the coupler parallel to the axis of the divider. According to the invention, each of these input junctions (J.sub.11, J.sub.12) has a rectilinear input branch (B.sub.1) with predetermined length such that the transverse distribution of the optical power at the output of the rectilinear input branch (B.sub.1) is centered to a large degree on the axis of this input branch.

Abstract: The fibers are connected to the component by adhesive means comprising a plurality of drops (11.sub.i, 12.sub.i) of an adhesive product, each of them fixing to the component between 1 and (N-1) adjacent fibers of the array, each of these drops being non-contiguous with at least one other of these drops, and at least one of the drops being longitudinally and laterally offset with respect to at least one other drop of the plurality.