Glass Drawing

Nearly all of CHI's products involve draw towers, on which we create our own optical fibers. The towers are also used to generate other critical components -- such as redrawn tubes, rods, etchable capillaries, and structures with custom cross-sections. Drawing our own material provides the flexibility to customize fibers and capillaries to meet diverse needs.

The draw process for a typical fiber is relatively straightforward. A glass assembly, consisting of a high-index glass rod inside of a lower-index glass tube, is suspended vertically above an oven into which it is lowered slowly. Once inside the heat zone, the lowest part of the glass softens and is pulled from below at a rate exceeding that of the feed into the oven. Mass in must equal mass out, which means that the cross-sectional area of the glass being pulled out of the oven must undergo a reduction to allow for the increase in length caused by the pull. This reduction can be described mathematically, and can be precisely controlled by the proper selection of the feed and draw rates. Thus, we can create fibers of practically any diameter from a core/clad combination of greater size.




About CHI | Products | Services | Publications | Contact CHI | Home