A new non-disturbing and wideband optical microsensor of electromagnetic fields

A new non-disturbing photonic probe for measuring electromagnetic (EM) powe r is presented. The sensing element is made of a silicon Fabry-Perot optica l microcavity connected to an optical fiber for remote interrogation. Preli minary measurements have been carried out in a non-optimized prototype in t he frequency range 2-18 GHz. They have shown the capability to detect minim um EM power densities of similar to 1.4 mW/cm(2). and a flat response at fr equencies greater than 10 GHz. A proper calibration makes the sensor useful an E-field probe. In this case, resolutions as low as 8 V/m have been meas ured. A simple theoretical analysis giving results in fair agreement with t he experiments is also reported. Simulations show that wide margins of opti mizations of the sensor exist. (C) 2000 Elsevier Science S.A. All rights re served.