Abstract: The present invention relates to an apparatus for carrying out a plasma chemical vapor deposition process by which one or more layers of doped or undoped silica can be deposited on the interior of an elongated glass substrate tube. The present invention further relates to a method for manufacturing an optical fiber using such an apparatus.

Abstract: A preform for manufacturing an optical fibre or an optical fiber, where the variation in the refractive index contrast of the preform does not exceed an absolute value of 2%, measured for a preform having a length of at least 60 cm, or the deviation of the preform in relation to the average value of the profile parameter ? does not exceed an absolute value of 0.03, measured for a preform having a length of at least 80 cm. The optical fibre has a deviation from the average value of the profile shape parameter ? of maximally about 0.03.

Abstract: The present invention relates to an apparatus for carrying out a PCVD deposition process, wherein one or more doped or undoped layers are coated onto the interior of a glass substrate tube, which apparatus comprises an applicator having an inner and an outer wall and a microwave guide which opens into the applicator, which applicator extends around a cylindrical axis and which is provided with a passage adjacent to the inner wall, through which the microwaves can exit, over which cylindrical axis the substrate tube can be positioned, and wherein at least one choke of annular shape having a length l and a width b is centred around the cylindrical axis within the applicator.

Abstract: The present invention relates to a method of manufacturing an optical fibre, which method comprises the following steps: i) providing a hollow substrate tube, ii) passing doped or undoped reactive, glass-forming gases through the interior of the hollow substrate tube, iii) creating such conditions in the interior of the hollow substrate tube that deposition of glass layers onto the interior of the hollow substrate tube takes place, wherein a non-isothermal plasma is reciprocated between two reversal points along the substrate tube, wherein the velocity of movement of the plasma decreases to zero at each reversal point, iv) collapsing the substrate tube thus obtained so as to form a solid preform, and v) drawing an optical fibre from said solid preform. In addition to that, the present invention relates to a preform for manufacturing an optical fibre, as well as to an optical fibre.