Multiaxis electric field sensing using slab coupled optical sensors.

This paper provides the details of a multiaxis electric field sensor. The sensing element consists of three slab coupled optical-fiber sensors that are combined to allow directional electric field sensing. The packaged three-axis sensor has a small cross-sectional area of 0.5 cm×0.5 cm by using an x-cut crystal. A method is described that uses a sensitivity-matrix approach to map the measurements to field components. The calibration and testing are described, resulting in an average error of 1.5°.

Electric-field sensors utilizing coupling between a D-fiber and an electro-optic polymer slab.

This paper provides a detailed analysis of electric field sensing using a slab-coupled optical fiber sensor (SCOS). This analysis explains that the best material for the slab waveguide is an inorganic material because of the low RF permittivity combined with the high electro-optic coefficient. The paper also describes the fabrication and testing of a SCOS using an AJL chromophore in amorphous polycarbonate. The high uniform polymer slab waveguide is fabricated using a hot embossing process to create a slab with a thickness of 50 µm. The fabricated polymer SCOS was characterized to have a resonance slope of ΔP/Δλ=6.83E5 W/m and a resonance shift of Δλ/E=1.47E-16 m(2)/V.

Electro-optic sensor from high Q resonance between optical D-fiber and slab waveguide.

An electro-optic sensor capable of detecting electric fields with a high degree of sensitivity and linearity is fabricated using optical D-fiber. The slab coupled optical sensor utilizes weak coupling and long evanescent interaction with a lithium niobate waveguide. Transmission dips from mode resonances have a linewidth of 0.12 nm and a Q factor of approximately 13,000. These sharp resonances improve device sensitivity and are achieved due to the unique fabrication process possible with D-shaped fibers. The sensor deviates <0.1% from linearity while monitoring fields between 200 V/m and 20 kV/m and promises high sensitivity to fields well beyond that range.

Electric field sensing with a hybrid polymer/glass fiber.

We demonstrate the operation of an in-fiber electric field sensor. The sensor is fabricated with selective chemical etching of the core of a D-shaped optical fiber followed by the deposition of an electro-optic polymer (PMMA/DR1), which forms a hybrid core. The device demonstrates electromagnetic field sensitivity less than 100 V/m at a frequency of 2.9 GHz. Epi is estimated to be 60 MV/m with an insertion loss of 14.4 dB.