Industrial standard mechanical polishing techniques are quite often used. There are special applications where even these high quality polishing procedures are not adequate. In these extremely demanding cases, computer automated laser machining developed by Polymicro has been used in many custom and production optical fiber finishing. Some of the shapes are shown in the previous section on sculpted tips. When silica on silica optical fiber is used, the cladding is left intact on several of the configurations. Most often, the configuration is rotationally symmetric about the fiber axis. This is not a rigid requirement. Many surface shapes and finishes can be applied to meet specific optical characteristic requirements. Features such as spiral grooves through the cladding, hemispherical or other shapes on the end, and various combinations of mechanical shapes can be engineered.