Photonic synthesis of high fidelity microwave arbitrary waveforms using near field frequency to time mapping

Abstract

Photonic radio-frequency (RF) arbitrary waveform generation (AWG) based on spectral shaping and frequency-to-time mapping has received substantial attention. This technique, however, is critically constrained by the far-field condition which imposes strict limits on the complexity of the generated waveforms. The time bandwidth product (TBWP) decreases as the inverse of the RF bandwidth which limits one from exploiting the full TBWP available from modern pulse shapers. Here we introduce a new RF-AWG technique which we call near-field frequency-to-time mapping. This approach overcomes the previous restrictions by predistorting the amplitude and phase of the spectrally shaped optical signal to achieve high fidelity waveforms with radically increased TBWP in the near field region.

A Review of Photonic Generation of Arbitrary Microwave Waveforms

“…As mentioned in Section 2, one of several approaches for photonic generation of arbitrary waveforms is Fourier Transform Pulse Shaping (FTPS) following by Frequency to Time Mapping (FTM) [12,22,23,29]. This approach exploits the broadband feature of photonics and its inherent large Time Bandwidth Product (TBWP).…”

“…To achieve this, sufficient dispersion in the order of the square of the optical pulse duration -also known as far field dispersion condition -must be satisfied [23]. Using a large dispersion can however limit the bandwidth and the upper frequency content of the generated waveforms due to the dispersion induced frequency fading effect [23] which is observed in the measurements of Figs. 5(a) and 5(b).…”

“…5(a) and 5(b). To overcome this limitation, a near field dispersion condition has been proposed and demonstrated [23]. In this later scheme, a significantly smaller dispersion than that would be required for far field condition is used resulting in the output temporal intensity depending on both the amplitude and the phase of the spectral profile making the process of FTM more complicated.…”

“…This paper provides a tutorial on photonic arbitrary waveform generations and reviews the three major approaches for AWG including i) Fourier Transform Pulse Shaping following by Frequency to Time Mapping [22][23][24][25][26], ii) Discrete Space to Time Mapping [27] and iii) Microwave Photonic (MWP) Filtering [1,8,28]. For each of these approaches, we explain the operation principle and presents selected results from the literature and highlight salient features.…”

Photonic-Assisted Error-Free Wireless Communication With Multipath Precompensation Covering 2–18 GHz

“…Electrical AWG offers long record length but restricted RF bandwidth due to speed limitations in digital-to-analogue conversion. In contrast, radio-frequency arbitrary waveform generation (RF-AWG) based on photonic techniques, especially those utilizing optical pulse shaping [15] and frequency-to-time mapping [16], [17], have experimentally demonstrated tens of GHz of RF bandwidth at center frequencies up to ∼100 GHz [18], [19]. In addition, its inherent compatibility with radio-over-fiber technology considerably reduces signal power loss during wired distribution [9].…”