Time lens induced by optical pushbroom effect

Abstract

We show analytically and by numerical simulation an on-chip time lens based on the optical pushbroom effect. Furthermore, we demonstrate this effect inside a silicon Bragg grating waveguide. A fast free carriers front generated inside the waveguide collects and traps the energy of a signal wave with smaller group velocity tuned near to the band gap of the waveguide with hyperbolic dispersion. The energy of the signal wave is accumulated inside the front and distributed in frequency. The presented effect can be utilized to compress signals in time and space.