摘要:
A method of measuring the twist imparted to an optical fibre includes the steps of advancing the optical fibre in a predetermined direction and at a predetermined velocity, imparting to the optical fibre, during the step of advancing, a twist about its axis, measuring the diameter of the optical fibre during the step of advancing, to generate a time-based signal indicating the diameter, and processing this signal to find a value indicating the imparted twist. The step of processing includes the principal steps of transforming in the frequency domain the signal relating to the measurement of the diameter, calculating the power spectrum of the signal thus obtained, distinguishing in this power spectrum the signal peaks correlated with the imparted twist, determining the maximum frequency associated with these signal peaks, and dividing the value of this maximum frequency by the value of the velocity of advance of the fibre to find the value indicating the imparted twist.
摘要:
Telecommunication cable comprising at least one microstructured optical fibre comprising a core region and a cladding region surrounding the core region, the cladding region comprising an annular void-containing region comprised of randomly arranged voids, the core region including doped silica to provide a positive refractive index relative to pure silica; and at least one protecting layer provided around said optical fibre, the protecting layer being made of a polymeric material having a low ultimate elongation.
摘要:
A method for producing an optical fiber having low polarization mode dispersion, by the steps of a) providing an optical fiber perform of glass material; b) heating the glass material of an end portion of the optical fiber perform; c) drawing the heated glass material at a drawing speed V to form an optical fiber, the drawn glass material having a viscous zone; and d) applying to the optical fiber a substantially sinusoidal spin, which is transmitted to the viscous zone, the spin function frequency ν , the viscous zone length L and the drawing speed V being such that both a torsion and at least a 50% detorsion are applied to the viscous zone.
摘要:
An apparatus and method for forming a optical fiber (102) which includes a furnace (104) for softening an optical fiber blank (106); a tractor (114) for drawing the optical fiber (102) from the softened optical fiber blank (106); and a first applicator (110) for applying a coating of a first coating material to the optical fiber (102), the first applicator having a rotatable die.