This dissertation presents the novel creation of a hybrid D-fiber electro-optic polymer electric field sensor. The sensor is made by removing a portion of the cladding from a D-shaped optical fiber, thus exposing the core to interaction with external stimulus. Then, an electro-optic polymer is deposited, partially replacing the core of the fiber. Next, the polymer is poled to endow it with electro-optic properties. This sensor is packaged in order to restore its mechanical strength. Because D-fiber is not intrinsically compatible with standard optical equipment it is fusion spliced to standard polarization maintaining fiber. Finally the sensor is tested for electro-optic sensitivity. The hybrid D-fiber electric field sensors designed and fabricated in this work meet the requirements of mechanical strength, temporal stability, minimal perturbation of the electric field by the sensor, and a small and flexible cross-sectional area so that it can be embedded into the device under test. A fully packaged hybrid electro-optic polymer D-fiber electric field sensor which is capable of detecting electric fields of 50 V/m at a frequency of 6 GHz is produced. The sensor's electro-optic response is shown to be temporally stable. Additionally, the sensor is physically robust, and physically and electrically non-intrusive. This work also adds a thorough understanding of the design and fabrication of D-fiber waveguides with a polymer material deposited in the core. Several new fabrication techniques are developed and presented. A path to greater electric field sensitivity is outlined for future research.