Novel structures in random hole optical fibers

In this paper, hybrid ordered hole-random hole optical fibers are proposed and presented for the first time. In normal PBF and MOF, the fibers consist of a composite of air (the ordered hole phase) and fused silica glass. Since these fibers are made with the tube stack and draw method, control of the refractive index inside the holes has not been feasible (unless a substance is infiltrated into the holes after fiber fabrication). Recent demonstration of the process to produce random hole optical fibers has opened up the potential for modulation of the refractive index inside the ordered hole region. By filling the tubes with the gas producing agent used in the random hole fiber, a new generation of fibers is now possible. The space which was originally air in the ordered holes of the fiber, can now be filled with a random hole region. Therefore, the average refractive index of the hole region can now be controlled over a wide range from essentially the refractive index of air to that of fused silica (hole completely filled). This allows a new range of fibers to be designed with the ability to tailor the refractive index of the hole region, and yet still maintain a pure silica glass fiber