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

Area of Science:

• Photonics
• Optical Signal Generation
• Waveform Synthesis

Background:

• Generating various optical waveforms is crucial for applications in optical communications and signal processing.
• Existing methods for waveform generation often face limitations in flexibility and complexity.

Purpose of the Study:

• To propose and demonstrate a new, flexible photonic scheme for generating diverse optical waveforms.
• To exploit the polarization-dependent characteristics of modulators for waveform synthesis.

Main Methods:

• Utilized two cascaded single-drive Lithium Niobate (LiNbO₃) Mach-Zehnder modulators as a pulse shaper.
• Arranged incident light polarization states to achieve distinct spectra on orthogonal polarization components.
• Superimposed photocurrents from orthogonal signals on a photodetector to obtain desired waveforms.

Main Results:

• Successfully generated square-shaped, triangular, and sawtooth waveforms experimentally.
• Demonstrated theoretical analyses and simulations supporting the experimental findings.
• Proposed and verified an approach to smooth sawtooth waveforms, reducing harmonic content.

Conclusions:

• The proposed photonic scheme offers a flexible and effective method for generating various optical waveforms.
• Exploiting modulator polarization dependence provides a powerful tool for optical signal shaping.
• The technique is suitable for generating complex waveforms with potential for further refinement.