A new hot-jointing technique for the preform fabrication of tellurite based single mode optical fibers

Abstract

The new preform fabrication technique, based on the direct-melt method and modified by the hot-jointing process, for tellurite based single mode optical fibers was developed. There are only some simple moulds needed, which are designed according to the dimension of the perform required. The different combinations of these moulds could be met the various requirements, such as the preform with high diameter ratio of cladding to core (DRCC) for single-mode optical fibers. The adoption of the hot-jointing method can prevent the preform from the fragile and inner stress comparing to the direct glass machining. This technique can also be used to fabricate other oxide and low melting point glasses. The jointing process is performed at a high temperature, which results in the core and cladding boundary melted well without the bubbles. The experimental results show that the large DRCC preforms could be made by this new technique, the preforms for drawing single mode optical fibers with the DRCC of 25 were fabricated. The single mode fibers were drawn from these preforms and the upconversion luminescence of Er3+ in the fiber with the length of 70cm could be observed.