Direct Optical Initiation (DOI), uses a moderate energy Q-switched Nd:YAG laser to shock initiate secondary
explosives, via either a flyer plate or exploding metal foil. DOI offers significant performance and safety advantages over
conventional electrical initiation. Optical fibers are used to transport the optical energy from the laser to the explosive
Energy densities in the region of 35 J cm-2 are required for initiation, significantly above the damage threshold of typical
optical fibers. Laser-induced damage is typically caused by laser absorption at the input face due to imperfections in the
surface polishing. To successfully transmit energy densities for DOI, a high quality fiber end face finish is required.
Fiber assemblies were prepared by C Technologies Inc, NJ, USA, with Innovaquartz FG365UEC optical fiber, using a
variety of polishing methods, with both steel and zirconia ferrules. The quality of the fiber end faces was assessed using
non-contact optical profilometry. The damage threshold for each polishing method was then determined using a Q-switched
Nd:YAG laser and the optimal polishing method determined for each ferrule material. Significant performance
differences between zirconia and steel ferrules were observed, and a physical cause of this difference is proposed.