Ultrahigh-Resolution Optoelectronic Vector Analysis for Characterization of High-Speed Integrated Coherent Receivers

An optoelectronic vector analyzer (OEVA), to characterize high-speed integrated coherent receivers (ICRs), is proposed and experimentally demonstrated, which has a capability of measuring the optoelectronic frequency responses including the magnitude response for each channel, the magnitude imbalance and the phase orthogonality between the two orthogonal channels. An optical double-sideband (ODSB) signal with suppressed carrier and a frequency-shifted carrier with known powers are, respectively, injected into the two input ports of the ICR under test. By detecting the frequency downconversion or upconversion component in the photocurrent from each output port, the magnitude response of each channel is obtained. By detecting the frequency downconversion or upconversion components from the two orthogonal channels simultaneously, the magnitude imbalance and the phase orthogonality are thus achieved. The proposed OEVA potentially has a sub-Hertz resolution in theory and is immune to the measurement errors induced by the high-order sidebands. In an experiment, a commercial high-speed ICR and a commercial high-speed photodetector (PD) are precisely characterized from 10 MHz to 50 GHz with a frequency resolution of 10 MHz.