Multi-axis all dielectric electric field sensors

This paper presents innovations that reduce the dimensions and interrogation complexity of a previously developed multi-axis electric field sensor. These devices are based on slab coupled optical sensor (SCOS) technology. SCOS are sensitive to electric fields that are parallel to the optic axis of the electro-optic slab. Electric fields are measured in two axes by mounting SCOS devices, which have slabs with optic-axes perpendicular to the fiber (z-cut), orthogonal to each other. In order to reduce dimensions of the sensor, the third-axis is measured by having a slab with the optic-axis parallel to the fiber (x-cut). Since the resonant mode coupling of a SCOS device occurs at specific wavelengths whose spectral locations are determined in part by the effective refractive index of the modes in the slab, rotating a z-cut slab waveguide relative to the optical fiber will cause the spectral position of the resonance modes to shift. This method allows the resonance modes to be tuned to specific wavelengths, enabling a multi-axis SCOS to be interrogated with a single laser source.