20 GHz arbitrary radio-frequency waveform generator based on incoherent pulse shaping

摘要

We demonstrate a new approach of photonically assisted radiofrequency(RF) waveform generation using a spectrally incoherent lightsource. The system is based on the so-called generalized frequency-to-timemapping operation. In this work, external modulation of the source is done by concatenating two electro-optic Mach-Zehnder modulators properlybiased to achieve short pulse gates which allow for broad bandwidthelectrical signals. Also, the spectral shaping stage is performed prior to O/E conversion. A detailed theoretical analysis demonstrates that even in thiscase the frequency-to-time mapping is preserved. The key is that the noiselevel is greatly reduced because the amplitude filter serves as noise rejecter.Experimental results show up to ~20 GHz electrical bandwidth signals using 10 Gb/s standard telecommunication equipment with the nice feature ofrepetition rate control on the generated electrical waveform.