Summary form only given. Anechoic chamber tests of several electromagnetic field detection systems have been performed. The performance of a 2-18-GHz externally modulated system consisting of a broadband cavity-backed spiral antenna, an optical waveguide modulator, a 1.32- mu m Nd:YAG solid state laser, single-mode optical fiber, and a high-speed photodiode was investigated. Operation with both III-V semiconductor based and lithium niobate based optical waveguide modulators has been investigated and compared for the externally modulated system. An rms electric field sensitivity of 15 mu V/m and a spurious free dynamic range of 102 dB in a 1 Hz resolution bandwidth have been measured with this 2-18 GHz field detection system. The performance of a 30 MHz-500 MHz directly modulated system consisting of a broadband VHF/UHF antenna, a laser diode, single-mode optical fiber, and a photodiode was also studied. For each field sensing system, the frequency response, electromagnetic field sensitivity, dynamic range, and environmental stability were investigated.
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