Photonics-Assisted Bandwidth-Doubling Dual-Chirp Microwave Signal Generation With Freely-Tunable Central Frequency

Abstract

A photonics-assisted dual-chirp microwave signal generation scheme is proposed based on electro-optic modulation and heterodyne detection. The dual-chirp microwave signal is generated by heterodyne beating between a dual-chirp optical waveform and a frequency-shifted optical carrier, where the dual-chirp optical waveform is obtained by applying a baseband symmetric-triangle linear frequency modulated signal to a Mach-Zehnder modulator biased at the minimum transmission point, and the frequency-shifted optical carrier is obtained by carrier-suppressed single-sideband modulation in a dual-parallel Mach-Zehnder modulator (DPMZM) with the assistance of an electronic 90° hybrid. The bandwidth of the generated dual-chirp microwave signal is twice of that of the input baseband signal, and the central frequency can be tuned by varying the frequency of the single-tone microwave signal applied to the DPMZM. Both numerical simulation and experiment are carried out to demonstrate the proposed scheme. In the simulation, a dual-chirp microwave signal with a center frequency of 15 GHz and a bandwidth of 6 GHz is generated. In the proof-of-concept experiment, dual-chirp microwave signals centered at 1.5 GHz and with bandwidth of 100 MHz and 200 MHz are generated, which verifies the feasibility of the proposed scheme.

Photonic-assisted generation of chirp microwave waveforms with switchable bands and immunity of dispersion-induced power fading

“…A bandwidth-doubling and frequencytunable dual-chirp microwave signal generation scheme is demonstrated based on electro-optic modulation and heterodyne detection. A dual-chirp microwave signal with double-bandwidth of the input baseband single chirp waveform is generated [15] . However, it has more clutter and poor carrier suppression ratio.…”

Linear dual-chirp microwave waveforms generation based on period-one state of integrated mutual injection laser

“…Therefore, researchers have turned to microwave photonics to achieve the generation of DCMW. [2][3][4][5][6][7][8] Currently, DCMWs is mainly generated by external modulation. For example, two Mach-Zehnder modulators are cascaded to produce DCMW, and two submodulators are used for carrier-suppressed single sideband (CS-SSB) modulation to produce DCMW [9].…”