An improved frequency-quadrupling triangular waveform generation based on external modulation and polarization control

Abstract

An improved photonic generation of full-duty-cycle triangular waveforms based on external modulation and orthogonal polarization control is proposed. The external modulation configuration consists a dual-parallel Mach–Zehnder modulator (DP-MZM) and a remodulation structure. After external modulation, four main sidebands with uniform frequency interval existed in the optical spectrum. To obtain the target triangular waveform, the modulation indices of modulators need to be carefully adjusted to guarantee the amplitude ration of inner-sideband and outer- sideband is desired 9.5 dB. Subsequently, polarization control is utilized to eliminate the coherent interference of different sidebands. Based on our proposal, triangular waveforms at 10 GHz, 20 GHz, 30 GHz and 40 GHz are achieved. The proposal might be attractive since that the generated signal repetition rate is frequency-tunable and frequency-quadrupled.

Keywords

• Microwave photonics
• Triangular waveform
• External modulation
• Polarization control