All-optical switching in 2D silicon photonic crystals with low loss waveguides and optical cavities

Il lavoro riporta la realizzazione sperimentale di commutazione tutto-ottica (all-optical switching) in guide d'onda a cristallo fotonico contenenti cavità, utilizzando la modifica dell'indice di rifrazione mediante eccitazione di portatori liberi come meccanismo di switching. Si tratta della prima dimostrazione a livello europeo dell'all-optical switching, ossia della realizzazione del principio del transistor ottico. Abstract: A study of the optical transmission of low-loss W1.5 photonic crystal waveguides built on silicon membranes and operating at telecom wavelengths is presented. The feasibility of performing all-optical switching is demonstrated for W1.5 waveguides coupled with L3 cavities, systems amenable for incorporation in on-chip devices. Switching of waveguide transmission is achieved by means of optical excitation of free carriers using a 2.5 ns pump laser. Experimental results are reproduced by finite-difference time-domain simulations which model the response of the finite system and band structure calculations describing the infinite, ideal one.