Rod-in-tube (RIT) method for the preparation of optical fiber preforms

The rod-in-tube (RIT) method is one of the conventional techniques used for optical fiber preform preparation. Interestingly, this term can also be found in other industries. In simple terms, it involves placing a glass rod inside a glass tube, heating the tube to melt it onto the rod, forming a thicker solid rod known as the optical fiber preform. Finally, one end of the preform is heated and stretched to form the optical fiber. RIT brings about various possibilities for specialty fiber development, and the tube-in-rod technique extends beyond the use in communication fibers. This technique enables more flexible fiber designs and paves the way for wider applications.