This paper demonstrates the value of D-type optical fibers (D-fibers) in a variety of sensing applications. The principal advantage of the D-fiber is that it allows for interaction with light traveling in the core of an optical fiber with materials or structures placed in contact with the fiber. This permits stimulus sensitive materials to be placed on the D-fiber to interact with the light in the core of the fiber. The presentation shows that this feature of D-fibers can be used to create alternatives to sensors formed in standard optical fibers for measuring temperature, strain, and shape change. In addition, D-fiber sensors have been fabricated to measure chemical concentrations, and electric fields.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.