Photonic Scheme for the Generation of Background-Free Phase-Coded Microwave Pulses and Dual-Chirp Microwave Waveforms

Abstract

We propose a photonic scheme to generate binary phase-coded microwave pulses and dual-chirp microwave waveforms without baseband-modulated signals (background noise) based on a dual-polarization dual-drive Mach-Zehnder modulator (DP-DDMZM) which contains x-DDMZM and y-DDMZM at two different polarization states. A radio frequency (RF) signal from a microwave source is transferred into two differential RF signals and employed into one arm of x-DDMZM and one arm of y-DDMZM, while a baseband signal from an arbitrary waveform generator is divided by an electronic coupler and then driven into the two other arms of DP-DDMZM. By adjusting the phase differences between the x-DDMZM and the y-DDMZM, binary phase-coded pulses and dual-chirp signals without baseband-modulated signals are generated. The proposed scheme can eliminate the interference caused by baseband-modulated signals, and satisfy different radar applications for different frequency bands. Experimental results show that phasecoded signals at 15 GHz with the bit rates of 1 Gb/s and 2 Gb/s and dual-chirp signals at 10 GHz and 15 GHz with the time durations of 0.5 μs are successfully generated. The reported scheme is well analyzed in theory and verified by experiment.

A review on photonic‐assisted dual‐chirp microwave waveform generation methods

“…Another method to generate dual‐chirp signal is discussed in references 19–23. They use dual‐polarization DPMZM configuration approach.…”

Photonic-Assisted Generation of Flexible and Switchable Multi-Band Linearly Frequency Modulated Microwave Waveforms

“…For generating dual-chirped waveforms, a series of photonic methods have also been reported. In [10]- [14], dual-chirped waveforms are obtained by utilizing a dual-parallel Mach-Zehnder modulator (DPMZM) [10], two cascaded MZMs [11], an integrated dualpolarization quadrature phase shift keying (DP-QPSK) modulator [12], an optically injected semiconductor laser [13] and dual-polarization dual-drive Mach-Zehnder modulator (DP-DDMZM) [14]. However, the above-mentioned approaches are only utilized to generate waveforms in a single format, which means they are suitable for scenarios that require single-chirped or dual-chirped signals.…”

Photonic generation of dual-band complementary linearly chirped microwave waveforms based on phase modulator

“…12 The dual-chirp waveform, which consists of both complementary linearly up-and down-chirps in the same time period, is produced based on a single dual-parallel Mach-Zehnder modulator (DPMZM) 12 and can address this issue. As an improvement in performance, the dual-chirp waveforms can also be generated based on a Fourier domain mode-locked (FDML) optoelectronic oscillator (OEO), 13 an optically injected semiconductor laser, 14 dual-polarization dual-drive Mach-Zehnder modulator, 15 a dual-polarization Mach-Zehnder modulator (DPol-MZM), 16 or a dual-drive Mach-Zehnder modulator (DDMZM). 17 However, the generated microwave waveforms based on the abovementioned approaches in the literature have only a single-frequency band.…”

“…Photonic-assisted chirped waveforms generation is one of the key techniques in the advanced radar systems, and many microwave photonic schemes have been reported 8 – 22 In Refs. 8–11, the linearly chirped microwave waveforms are generated with increased time-bandwidth product (TBWP) by the external modulation.…”