Electro-optic time lens with an extended time aperture

Abstract

We propose what we believe to be a new approach to correct the residual aberrations of time lenses implemented through electro-optic sinusoidal phase modulation. The method is based on a single modulator driven with various harmonic channels coming from the same clock signal. Proper weighting of the amplitude and phase of the channels allows us to achieve nearly perfect parabolic phase modulation over a fraction of the clock period. We show numerically that our proposal only requires three harmonics of the clock frequency to achieve truly parabolic modulation over a time window that extends across 70% of the period. We illustrate the benefits of this aberration-free scheme in a pulse compression scenario and compare its performance with previous conventional Fourier optimization techniques. Our study offers simple guidelines to achieve indeed quadratic phase modulation in situations where electro-optic phase modulation in lithium niobate is required, such as integrated frequency comb technology or high-speed optical pulse shaping.