Ultrafast optical switching using photonic molecules in photonic crystal waveguides

Abstract

Abstract:We study the coupling between photonic molecules and waveguides in photonic crystal slab structures using finite-difference time-domain method and coupled mode theory. In a photonic molecule with two cavities, the coupling of cavity modes results in two super-modes with symmetric and anti-symmetric field distributions. When two super-modes are excited simultaneously, the energy of electric field oscillates between the two cavities. To excite and probe the energy oscillation, we integrate photonic molecule with two photonic crystal waveguides. In coupled structure, we find that the quality factors of two super-modes might be different because of different field distributions of super-modes. After optimizing the radii of air holes between two cavities of photonic molecule, nearly equal quality factors of two super-modes are achieved, and coupling strengths between the waveguide modes and two super-modes are almost the same. In this case, complete energy oscillations between two cavities can be obtained with a pumping source in one waveguide, which can be read out by another waveguide. Finally, we demonstrate that the designed structure can be used for ultrafast optical switching with a time scale of a few picoseconds.

Optical Polarization Sensitive Ultra-Fast Switching and Photo-Electrical Device

“…Most of these techniques use special materials, such as Potassium Lithium Tantalum Niobate (KLTN) crystals [4]. Others are based on molecules [5] or Gallium phosphide (GaP) [6]. One can now imagine how useful the switching effect for micro-electronic needs could be when using a silicon-based device.…”

Photonic molecules for improving the optical response of macroporous silicon photonic crystals for gas sensing purposes

“…If a new cavity or a set of them is added to the structure, the optical response cannot only be enhanced but also new functionalities of the system can be obtained. Photon hopping, which consists in the energy transference between adjacent cavities, is one of the most relevant properties of PMs that find its application in coupled-resonator optical waveguides [10][11][12], optical switching [13,14] or quantum information processing [15,16], among others. Furthermore, it has been shown that this energy transfer can be tuned depending on the inter-cavities conformation and on the morphology of the cavities themselves [17,18], leading to enhanced bandwidths and boosted Q-factors [19,20].…”

All-Optical Switching Based on the Plasma Channel Induced by Laser Pulses

“…Owing to special properties of controlling light propagation, photonic crystals are thought to have promising future in all-optical switching. Two photonic crystal (PC) cavities, metallic PC, and electromagnetically induced transparency in PC nanocavities [6,7] are reported to use for all-optical switching. Thanks to strong localized field enhancement effect, high localization, and the breakthrough of the diffraction limit, surface plasmon is chosen to realize ultrafast all-optical switching with few energy consumption.…”