Time-Interleaved 20-GHz Modulated Wideband Converter Based on Random Optical Sampling

In this letter, time-interleaved multiwavelength pseudorandom binary sequence (PRBS) optical pulses are utilized to significantly increase the instantaneous bandwidth of the modulated wideband converter (MWC). A four-channel MWC with a bandwidth of 20 GHz is proposed for the first time, where four-wavelength optical pulse trains modulated by a 10.16-Gb/s PRBS signal are interleaved temporally after going through four sections of fibers with different lengths in parallel. The flat and ultrawide spectrum of the PRBS-modulated pulse train guarantees a uniform SNR and recovery probability. Sparse radio frequency signals ranging from 0.5 to 20 GHz are reconstructed faithfully from four-channel samples with only 360-MHz bandwidth.