All-optical switching in a laterally coupled microring resonator by carrier injection

We demonstrate all-optical switching in a laterally coupled GaAs-AlGaAs microring resonator by carriers injections. The ring waveguide is optically pumped just above its bandgap energy, which results in a temporal tuning of the microring resonant wavelengths by the refractive index change due to the induced carriers. A switching window of 20 ps could be obtained and is only limited by the carrier recombination time. A switching energy of a few tens of picojoules per pulse is used and has resulted in a 1.2-nm wavelength shift of the microring resonance.