Photonic generation of high-accuracy triangular waveform with tunable duty cycle based on a dual-wavelength I/Q modulation.

The photonic generation of high-accuracy triangular waveforms with a tunable duty cycle based on a dual-wavelength in-phase/quadrature-phase (I/Q) modulation is proposed and analyzed. By adjusting the modulation index, the phase shift caused by the electric phase shifter and the bias voltage of the modulator, the optical signals of the upper and lower paths can be superimposed and then passed through the bandwidth limited photodetector to obtain a triangular wave, form with a tunable duty cycle ranging from 0.1≤σ≤0.9. High-order harmonic Fourier series components are used to construct the high-accuracy function waveform. It is found that the waveform rms error can be greatly decreased (around two-time performance improvement with duty cycle 0.1≤σ≤0.9). To evaluate the feasibility of our proposal, the effects of modulation index drift, bias voltage drift, and phase shift drift on the obtained waveform are also discussed. [ABSTRACT FROM AUTHOR]