Zhang, BoyiBoyiZhangLi, HeHeLiCai, XinlunXinlunCaiVega, FelixFelixVegaLi, JuntaoJuntaoLiEich, ManfredManfredEichPetrov, AlexanderAlexanderPetrovGaafar, Mahmoud AbdelazizMahmoud AbdelazizGaafar2026-02-062026-02-062026-01-23Scientific Reports 16 (1): 3050 (2026)https://hdl.handle.net/11420/61333Here we report the first experimental demonstration of signal trapping by a refractive index front in a silicon waveguide with a periodic perturbation, the so-called optical push broom effect. The refractive index front generated by a fast pump pulse captures and confines the energy of a CW signal propagating with smaller group velocity near to the band gap of a Bragg grating introduced in the waveguide. The energy of the CW signal is shifted in frequency, accelerated to the front velocity and thus accumulated inside the front. In the experiment a 2 ps free carrier front was generated via two photon absorption of the pump in the silicon waveguide. It collects approximately a 30 ps long packet of the CW signal inside it. The presented effect can be utilized to compress signals in time and space.en2045-232220261Nature Researchhttps://creativecommons.org/licenses/by/4.0/Nonlinear pulse propagationOptical push broomSignal trappingSilicon waveguideNatural Sciences and Mathematics::530: PhysicsTechnology::621: Applied Physics::621.3: Electrical Engineering, Electronic EngineeringJournal Articlehttps://doi.org/10.15480/882.1663510.1038/s41598-026-36302-x10.15480/882.16635Journal Article