Photonic compressive sensing of sparse radio frequency signals with a single dual-electrode Mach–Zehnder modulator

Abstract

A novel approach to realizing compressive sensing (CS) of sparse radio frequency (RF) signals based on photonic random demodulation (RD) is proposed. The key function of mixing the RF signal under test and the bipolar pseudo-random binary sequence (PRBS) in photonic RD is implemented with a single dual-electrode Mach–Zehnder modulator (DEMZM). By properly setting the DC bias of the DEMZM at V π and the voltages of the PRBS at ± V π / 2 , a pure desired multiplication term between the signal and the bipolar PRBS is obtained after an AC-coupled photodetector (PD), which not only simplifies the modeling of the CS link but also improves the recovery performance. A proof-of-concept experiment is demonstrated where a sparse signal with spectral components of 500 MHz and 950 MHz is successfully identified with a compression ratio of 20. Simulation results are also given to show the advantage of the given photonic CS scheme with bipolar random mixing.

Mitigating the impact of non-ideal PRBS on photonics-assisted compressive sensing systems through complementary PRBS and parallel links

“…The reconstructed results are shown in Figure 2(a). Compared with the results when the single RD structure is used [4], the quality of the recovered signal can be well improved by the proposed method, no matter the sampling point after undersampling is at any position of a PRBS code period. The average reconstruction error of the 16 reconstructions for the three-tone signal is decreased from 0.163 to 0.094 through parallel processing.…”

“…In addition, from the perspective of spectrum, the proposed method can also recover the relationship between different frequencies more accurately. In addition, comparing Figures 2(c) and (e), it can be seen that the single RD structure [4] is not only not accurate enough to recover the frequency relationship but also produces an unwanted spurious frequency. Then, the proposed method is further investigated by using a more complex five-tone signal.…”

“…After reconstruction by the orthogonal matching pursuit algorithm, the recovered signal x is obtained. The signal recovery is repeated 16 times at 16 different positions in the middle of a PRBS code period, and the reconstruction errors are estimated by 22 22 / x x x  − [4]. The reconstructed results are shown in Figure 2(a).…”

“…Photonic RD is a simple but effective method for implementing photonics-assisted CS. Various configurations for photonic RD have been proposed [3,4]. These schemes perform frequency mixing between the incoming signal and a pseudo-random binary sequence (PRBS) in the optical domain via a photonic RD.…”

“…The schematic diagram of the proposed parallel photonics-assisted CS system is shown in Figure 1(a). As can be seen, compared with a commonly used photonics-assisted RD employing a single DD-MZM [4], another DD-MZM is added and paralleled with the first DD-MZM in the structure. The optical carrier emitted by the LD is split into two branches and injected into the two DD-MZMs, respectively.…”