Photonic microwave waveforms generation based on two cascaded single-drive Mach-Zehnder modulators

Abstract

A new photonic scheme for various waveforms generation has been proposed and demonstrated. In the scheme, two cascaded single-drive LiNbO Mach-Zehnder modulators serve as pulse shaper and the polarization-dependent character of the modulators is fully exploited and utilized. By arranging the polarization states of the incident light, two different spectra are achieved on two orthogonal polarization components respectively. Finally, the desired waveforms can be obtained by superimposing the photocurrents of the two orthogonal signals on a photodetector. The detailed theoretical analyses and simulations are given. In the experiment, square-shaped waveform, triangular waveform and sawtooth (or reversed-sawtooth) waveform are obtained successfully. Furthermore, an approach to smoothing the sawtooth waveform with fewer harmonics is suggested and verified.

Microwave Photonic Signal Generation in an Optically Injected Discrete Mode Semiconductor Laser

“…Compared with microwave synthesis using electronics, which has been extensively explored and developed over the past decades, high-frequency microwave photonic (MWP) signal generation in the optical domain is more convenient and cost-effective. Various approaches of MWP signal generation can generally be classified into optical heterodyning [13,14], direct and external modulation [15][16][17], self-pulsating and mode-locking [18,19], optoelectronic oscillators (OEOs) [20][21][22][23][24], and laser dynamics of period-one (P1) [25][26][27][28][29][30][31][32][33][34][35][36]. The optical heterodyne technique can easily achieve terahertz photonic microwaves by beating between two optical beams with certain wavelength spacing, as such the technique has very wide tunability [13].…”

A Photonic-Assisted Generation of Triangular Waveform With Frequency Octupling

“…In these schemes, no additional radio frequency (RF) source is required. In addition, triangular waveform generation based on time-domain synthesis (TDS) has also been proposed recently [12][13][14][15][16]. In Ref.…”

“…In Ref. [14][15][16], triangular waveform generation methods based on waveform time-domain synthesis in MZMs at different modulation modes are presented. In addition to the proposals mentioned above, schemes based on external modulation cooperated with spectrum manipulation are also widely studied [17][18][19][20][21][22][23][24].…”

Photonic Generation of Triangular-Shaped Waveform With Tunable Symmetry Factor Based on Two Single-Drive Mach-Zehnder Modulator

“…A large number of schemes for symmetrical triangular waveform generation based on this method have been reported in the past decades, such as based on a single-drive Mach-Zehnder Modulator [7], modulator combined with dispersive fiber [8], [9], modulator combined with filter [10], [11], modulator combined with polarization devices [12], [13], stimulated Brillouin scattering [14] and optoelectronic oscillator [15]- [16]. Based on external modulation, the researchers also have proposed many schemes for generating sawtooth waveform [17]- [19]. However, the symmetry of the generated waveform is not tunable whether it is symmetrical triangular waveform or sawtooth waveform, which limits the application range of the triangular-shaped waveform.…”