Linear 1×2 directional coupler for electromagnetic field detection

Abstract

A 1×2 directional coupler which can be used as an integrated optical electromagnetic field detector is described. Modulators have been formed from titanium-indiffused lithium niobate waveguides operating at the 1.3 μm wavelength. Linear dynamic ranges of 74.3 dB with 190 μW light and 76.3 dB with 760 μW light were observed for separate devices. Voltage sensitivity measurements are in good agreement with theoretical predictions. A 3.1 μV rms sensitivity was obtained for a device with a 10 mm electrode length.