Gold Coated VO2 Nanogratings Based Plasmonic Switches

This paper presents 2 dimensional (2D) and 1 dimensional (1D) gold (Au) coated VO2 (Vanadium Dioxide) nanogratings based tunable plasmonic switch. VO2 is a phase changing material and hence exhibits phase transition from semiconductor to metallic phase approximately at 67 ºC or 340 K (critical temperature) which can be achieved by exposure to IR radiation, application of voltage, heating, etc. and there is a huge contrast between optical properties of its metallic and insulating phases and hence that can be utilized to implement VO2 based optical switches. These VO2 based gratings couple the incident optical radiation to plasmonic waveguide modes which in turn leads to high electromagnetic field enhancement in the gaps between the nanogratings. The proposed Au coated VO2 nanogratings can be fabricated by using current state of art fabrication techniques and provides switchability of the order of femtoseconds. Hence the optical switching explained in our paper can be used fast switching applications. For an optimum switch our aim is to maximize its differential reflectance spectra between the 2 states of VO2, i.e., metallic and semiconductor phases. Rigorous Coupled Wave Analysis (RCWA) reveals that wavelengths for maximum differential reflectance can be optimized over a large spectral regime by varying various parameters of nanogratings for example groove height (h), width (w), gap (g) between the gratings, and thickness (t) of Au coating over VO2 by simulation using RCWA for maximum differential reflectance between VO2 metal and semiconductor phase, i.e., the switching wavelengths can be tuned by varying grating parameters and thus we can have optimum optical switch.

A Full-Duplex 5×5 Optical Router Based on a Hybrid Photonic-Plasmonic Switch

An optical router is an essential component of a photonic network-on-chip (PNoC). Normally, an optical router consists of traditional optical elements such as the micro-ring resonator (MRR) and the Mach-Zehnder interferometer (MZI). This type of router has many disadvantages, such as a large size, lack of thermal stability and low speed, although their manufacturing technologies are mature. In this paper, we propose a full duplex 5×5 optical router based on a hybrid photonic-plasmonic switch (HPPS). The HPPS has the advantages of compactness, thermal stability and high speed, which can effectively solve the problems of traditional optical routers. In this work, each optical communication link in the optical router is independent, and each optical communication link no longer shares the same switch, which avoids blocking between channels and achieves full-duplex communication. The modelling of the optical router using the HPPS is performed through MATLAB as well as by a finite-difference-time-domain (FDTD) simulation. The maximum and average insertion losses (ILs) of the router are 5.4 dB and 3.5 dB, respectively, and the router has a fast switching time (100 ps). The results show that this optical router has the advantages of low loss and low energy consumption and provides a 5×5 full-duplex optical router for the PNoC.

Plasmonic switch Based on asymmetric cavities with embedding square of gold inside the cavities

In this paper, we proposed an all-optical plasmonic switch based on metal-insulator-metal (MIM) structures. We used the intrinsic nonlinear properties of gold to implement the switch. The proposed switch consists of a bus waveguide side coupled with a pair of asymmetric vertical cavities. We obtained the transmission spectrum of the structure for low input intensities. The results showed that a sharp dip occurs at the wavelength of 860 nm. Due to the nonlinear properties of gold and the nonlinear Kerr effects, the proposed switch has a high transmission ratio of about 0.8 and a low threshold power of 0.07 mW/µm2. The threshold power of the structure with and without using the gold nanostructure shows a reduction of 50%. The result showed that the proposed switch has the potentiality to be applied in the plasmonic integration circuits.