G652D is a rigid fiber with limited bending resistance and a minimum bending radius of 30mm. It is one of the categories defined by the International Telecommunication Union (ITU-T) under the G. Among them, G652 fibers are the most commonly used. 1 What is G652D fiber, and how does it work? What is G652D fiber, and how does it work? G652D optical fiber has been in. Fiber optic cables are the ultimate technology used in data transfer using light waves.