Improvements in electric-field sensor sensitivity by exploiting a tangential field condition

This paper presents improvements to slab-coupled optical fiber sensors for electric-field sensing. The sensors are comprised of a potassium titanyl phosphate (KTP) crystal mounted on a D-fiber. The improvements are based on changing the crystal orientation, which enhances sensitivity due to a combined increase in the effective electro-optic coefficient and electric-field penetration into the KTP crystal. The paper provides a detailed comparison of the improved sensor, which uses x-cut KTP to the previous sensor design using z-cut KTP. The measurements show an 8.6× improvement in the sensitivity.