Nonsymmetrical modified chemical vapor deposition (N-MCVD) process (optical fibres)

A novel, simple fabrication method of circularly and axially nonsymmetrical MCVD layers is proposed. The thermophoretic mechanism is regulated by means of two linear heaters and coolers, respectively which change the circular symmetry of the thermophoretic deposition mechanism of the standard MCVD process. A theoretical description of the thermophoretic deposition mechanism inside the substrate tube in some simplified conditions is given. The differential equations governing mass transport through the thermophoretic effect are solved in closed form. As an example a preform of the dumbbell form core has been fabricated.<
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