Performance analysis of optical vector analyzer based on optical single-sideband modulation

Optical vector network analyzers (OVNAs) based on optical single-sideband (OSSB) modulation are of great interest thanks to the potentially high measurement resolution. However, the measurement accuracy of the OSSB-based OVNA is limited by the high-order sidebands in the OSSB signal. To study the influence of the high-order optical sidebands in OSSB signals on the measurement accuracy, an analytical model is established to present the expression of the measurement error and a numerical simulation is performed. For the OSSB-based OVNA implemented by a 90-deg electrical hybrid coupler and a dual-drive modulator, when the −1st order sideband is fully suppressed by the OSSB modulation, the existence of the +2nd-order sideband severely degrades the resolution of the measurement, while the −3rd and −2nd order sidebands place a restriction on the dynamic range of the measurement. In addition, these sidebands also introduce evident measurement errors to the phase response. The study may provide a good guidance in designing the high performance OVNA.