A 210-GHz bandwidth electrooptic sampler for large signal characterization of InP-based components

We propose an electrooptic sampler at 1.55 mu m (wavelength), which uses an ion-irradiated InP-based photoconductor for the optical-to-electrical conversion and a fiber-mounted LiTaO3 crystal as the electric-field sensor. A measurement bandwidth of 210 GHz is obtained with a signal-to-noise ratio higher than 17 dB. These results are found to be independent of the amplitude of the 2.1-ps excitation pulse, which reaches values as high as 0.81 V. Large signal characterization of InP-based components are thus allowed. The performance of our system is validated by test measurements performed on coplanar waveguides made on semi-insulating InP substrates.