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In this paper, all-optical plasmonic switches (AOPS) based on various configurations of circular, square and octagon nonlinear plasmonic ring resonators (NPRR) were proposed and numerically investigated. Each of these configurations consisted of two metal-insulator-metal (MIM) waveguides coupled to each other by a ring resonator (RR). Nonlinear Kerr effect was used to show switching performance of the proposed NPRR. The result showed that the octagon switch structure had lower threshold power and higher transmission ratio than square and circular switch structures. The octagon switch structure had a low threshold power equal to 7.77 MW/cm2 and the high transmission ratio of approximately 0.6. Therefore, the octagon switch structure was an appropriate candidate to be applied in optical integration circuits as an AOPS.

An all-optical switch based on nonlinear photonic crystal ring resonator embedded with silica dielectric surrounded by silver nanoshell (NS) inside the ring resonator has been introduced and analyzed in this article. We considered silica with radius of 10 nm and silver with radius of 16 nm as core and shell, respectively. By placing NSs inside the photonic crystal ring resonator, we succeeded in reducing the threshold power to 12.8 mW/μm 2 and the switching time to about 0.4 ps. The results of this research suggest a new technique for reducing switching light intensity. With small size, ultra-fast switching time, and low-threshold power, the structure has the potential to be applied in optical integration circuits and nanoscale optical chips.

In this paper, we investigate the application of Kerr-like nonlinear photonic crystal (PhC) ring resonator (PCRR) for realizing a tunable full-optical add–drop filter. We used silicon (Si) nano-crystal as the nonlinear material in pillar-based square lattice of a 2DPhC. The nonlinear section of PCRR is studied under three different scenarios: (1) first only the inner rods of PCRR are made of nonlinear materials, (2) only outer rods of PCRR have nonlinear response, and (3) both of inner and outer rods are made of nonlinear material. The simulation results indicate that optical power required to switch the state of PCRR from turn-on to turn-off, for the nonlinearity applied to inner PCRR, is at least $$2000\, \hbox {mW}{/}\upmu \hbox {m}^{2}$$ and, for the nonlinearity applied to outer PCRR, is at least $$3000\, \hbox {mW}{/}\upmu \hbox {m}^{2}$$ which corresponds to refractive index change of $$\Delta n_\mathrm{NL }= 0.085$$ and $$\Delta n_\mathrm{NL }= 0.15$$ , respectively. For nonlinear tuning of add–drop filter, the minimum power required to 1 nm redshift the center operating wavelength $$(\lambda _{0} = 1550\, \hbox {nm})$$ for the inner PCRR scenario is $$125\, \hbox {mW}{/}\upmu \hbox {m}^{2}$$ (refractive index change of $$\Delta n_\mathrm{NL}= 0.005)$$ . Maximum allowed refractive index change for inner and outer scenarios before switch goes to saturation is $$\Delta n_\mathrm{NL }= 0.04$$ (maximum tune-ability 8 nm) and $$\Delta n_\mathrm{NL }= 0.012$$ (maximum tune-ability of 24 nm), respectively. Performance of add–drop filter is replicated by means of finite-difference time-domain method, and simulations displayed an ultra-compact size device with ultra-fast tune-ability speed.

Here, we propose a full-optical tunable Add/Drop filter based on single (SR) and double-vertically (DR) aligned Kerr-like nonlinear photonic crystal ring resonators (PCRRs). Silicon (Si) nano-crystal is used as the nonlinear material inside and outside of PCRRs. The minimum optical power required to turn–on/turn–off the SR and DR filters are 2000 mW/μm 2 , and 150 mW/μm 2 , respectively. We believe since the DR filter has a higher Q -factor rather than SR and also since the optical power reads more nonlinear rods with a longer time to pass the structure, thus the optical power required is much lower (10 folds). In addition, the minimum power required to 1 nm redshift the center operating wavelength of SR filter is 125 mW/μm 2 (i.e. Δ n NL = 0.005) and for DR is as low as 8 mW/μm 2 . Performance of the Add/Drop filter structure is simulated by means of finite difference time domain (FDTD) method, in which the simulations showed an ultra-compact size structure with promising ultrafast tune-ability speeds.

A novel all-optical switch based on nonlinear photonic crystal ring resonator with embedding metallic nanowires in the ring resonators has been simulated and analyzed by the finite difference time domain method. We placed Ag-nanowires inside the ring resonator to reduce light intensity. The ring resonator has a low switching time of about 0.6 ps and low switching power equal to 36.5 mW/µm2. Since the structure is of small size and ultra-fast time, it has the potentiality to be applied in optical integration circuits and nano-plasmonic information processing.