Design And Simulation Of Integrated Nanophotonic Waveguide Devices

Increasing the integration density of devices and communication capacity are the development trend and current challenge of optical communication devices. Modern electronic devices for information processing is rapidly approaching its fundamental speed and bandwidth limitations, which is an increasingly serious problem that impedes further advances in communications and other technologies.One of the most promising solutions is to use the light wave as the information carrier. However, light in dielectric media has a diffraction limit, which limits the integration density of optical communication devices. Surface plasmon polariton(SPP) waveguides, which utilize the interaction of light and collective oscillations of electron plasma in the metal, can break the diffraction limit and confine light in a nanoscale region, resulting in the great increase of integration density of devices.In this thesis, we combine the advantages of long-range SPP waveguide, hybrid SPP waveguide and wedge SPP waveguide, and bring forward a long-rang hybrid wedge plasmonic waveguide. We simulate the mode properties of the designed waveguide using a finite element method. The obtained results indicate greatly reduced propagation loss under a similar level of mode confinement. We also analyze the fabrication method of the waveguide and discuss the impact of fabrication tolerance on the mode properties. The obtained results show favorable waveguide fabrication tolerance under a wedge angle of 140 degree. In addition, we design a long-range hybrid slot plasmonic waveguide. By exploiting the non-degenerate four-wave mixing in such waveguide, we propose and simulate all-optical switching.From the aspect of increasing the communication capacity, on-chip mode multiplexing based on silicon waveguide can provide a new dimension to increase the communication capacity, which is similar to wavelength multiplexing and other multiplexing techniques. In this thesis, by exploiting tapered asymmetric directional coupler on silicon-on-insulator platform, we design and simulate mode exchange and mode multicasting devices which can be used in on-chip mode multiplexing systems. The obtained simulation results show that the proposed device can realize efficient mode multiplexing, mode exchange and mode multicasting. Moreover, the insertion loss is small and the fabrication technique is simple.