Chapter 2: The Basic Theory and Method
3.3 Simulation and Results
3.3.1. AND gate
We use the proposed plasmonic waveguide structure with eight-disk resonators filled with a Kerr-type nonlinear material to design an AND logic gate, as shown in Fig.
3.8. Before design the logic gate, we must first investigate the two straight pumping waveguide L1 and L2 and coupling length g the influence. First, we are the proposed plasmonic waveguide structure, as shown in Fig. 3.8, to design an all-optical AND logic gate. The parameters of the proposed structure are chosen R1 = 295 nm, R2 = 290nm, R3
= 285 nm, R4 = 280 nm, h = 100 nm, w = 50 nm, w1 = 20 nm, w2 = 30 nm, d1 = 20nm, d2 = 240nm. In the Figure 3.9 and Tab 3.2 shows the band-stop efficiency in wavelength of 1310nm for different length of pumping waveguide. Basis the simulation results, we found that the best length L1 is 400 nm. Next, we change L2 from 100nm to 500nm. In Figure.3.10 and Tab. 3.3 we find the transmission efficiency at L2 = 300nm, the trough
wavelength at 1310nm minimum transmittance is 0.002%. Next, we investigate the distance d1 between the nano-disk cavities and waveguide. In Figs. 3.11, the distance d1
is varying from 0nm to 220nm. When d1 =20nm, we can get the better band-stop and band-pass results. Then we use the same method to investigate the transmission spectra for different gap distance between the straight pumping waveguide and the bus waveguide. In Fig. 3.12 shows that when g = 50nm, we can obtain the best band-pass transmission efficiency. In this structure, the signal port is always ON with the input intensity I0=1x106 V2/m2.
When the control ports A and B are both OFF, the output port is OFF. The magnetic field distribution is shown in Fig. 3.13 (a). The normalized transmission efficiency at light intensity I1=5x107 V2/m2, the output port is OFF. The magnetic field distribution is shown in Fig. 3.15 (a). The transmission efficiency at the wavelength 1310nm is about 0.004%, as shown in Fig. 3.15 (b). When both the control ports A and B are ON with the input light intensity I1=5x107 V2/m2, the output port is ON. The magnetic field distribution is shown in Fig. 3.16 (a). The normalized transmission efficiency at the wavelength 1310nm is about 94.5%, as shown in Fig.3.16 (b). The truth table and the transmission efficiency are shown in Tab. 3.4.
3.3.2. OR Logic gate
We use the proposed plasmonic waveguide structure with eight-disk resonators filled with a Kerr-type nonlinear material to design an OR logic gate, as shown in Fig. 3.8.
The magnetic field distribution is shown in Fig. 3.17 (a). The transmission efficiency at the wavelength 1310nm is about 0.002%, as shown in Fig. 3.17 (b). When the control port A is OFF and the control port B is ON, with the input light intensity I1=1x108 V2/m2, the output port is ON. The magnetic field distribution is shown in Fig. 3.18 (a).
The transmission efficiency at the wavelength 1310nm is about 94.5%, as shown in Fig.
3.18 (b). When the control port A is ON, with the input light intensity I1=1x108 V2/m2 and the control port B is OFF, the output port is ON. The magnetic field distribution is shown in Fig. 3.19 (a). The transmission efficiency at the wavelength 1310nm is about 94.3%, as shown in Fig. 3.19 (b). When both the control ports A and B are ON, with the input light intensity I1=1x108 V2/m2, the output port is ON. The magnetic field distribution is shown in Fig.3.20 (a). The transmission efficiency at the wavelength 1310nm is about 95.4%, as shown in Fig.3.20 (b). The truth table and the transmission efficiency are shown in Tab. 3.5.
3.3.3. NOR Logic gate
We use the proposed plasmonic waveguide structure with eight-disk resonators
filled with a Kerr-type nonlinear material to design an NOR logic gate, as shown in Fig. transmission efficiency at the wavelength 1310nm is about 97.4%, as shown in Fig. 3.21 (b). When the control port A is OFF and the control port B is ON, with the input light intensity I1=5x107 V2/m2, the output port is OFF. The magnetic field distribution is shown in Fig. 3.22 (a). The transmission efficiency at the wavelength 1310nm is about0.005%, as shown in Fig. 3.22 (b). When the control port A is ON, with the input light intensity I1=5x107 V2/m2 and the control port B is OFF, the output port is OFF. The magnetic field distribution is shown in Fig. 3.23 (a). The transmission efficiency at the wavelength 1310nm is about 0.006%, as shown in Fig. 3.23 (b). When both the control ports A and B are ON, with the input light intensity I1=5x107 V2/m2, the output port is OFF. The magnetic field distribution is shown in Fig.3.24 (a). The transmission efficiency at the wavelength 1310nm is about 0.007%, as shown in Fig.3.24 (b). The truth table and the transmission efficiency are shown in Tab. 3.6.
3.3.4. XNOR Logic gate
We use the proposed plasmonic waveguide structure with eight-disk resonators filled with a Kerr-type nonlinear material to design an XNOR logic gate, as shown in Fig. 3.8. The parameters of the proposed structure are chosen R1 = 280 nm, R2 = 275nm, R3 = 270 nm, R4 = 265 nm, h = 100 nm, w = 50 nm, w1 = 20 nm, w2 = 30 nm, d2 =
240nm, L1 = 400nm, L2 = 300nm, g = 60nm. Next, we change the input intensity to achieve the XNOR logic gate. In this stage, signal port is always ON with the input light intensity I0=1x106 V2/m2. When the control ports A and B are both OFF, the output port is ON. The magnetic field distribution is shown in Fig. 3.25 (a). The transmission efficiency at the wavelength 1310nm is about 97.4%, as shown in Fig. 3.25 (b). When the control port A is OFF and the control port B is ON, with the input light intensity wavelength 1310nm is about 0.005%, as shown in Fig. 3.27 (b). When both the control ports A and B are ON, with the input light intensity I1=1x108 V2/m2, the output port is ON. The magnetic field distribution is shown in Fig.3.28 (a). The transmission efficiency at the wavelength 1310nm is about 94.6%, as shown in Fig.3.28 (b). The truth table and the transmission efficiency are shown in Tab. 3.7.
3.3.5. NAND Logic gate
We use the proposed plasmonic waveguide structure with eight-disk resonators filled with a Kerr-type nonlinear material to design an NAND logic gate, as shown in Fig. 3.8. The parameters of the proposed structure are chosen R1 = 270 nm, R2 = 265nm, R3 = 260 nm, R4 = 255 nm, h = 100 nm, w = 50 nm, w1 = 20 nm, w2 = 30 nm, d2 = 240nm, L1 = 400nm, L2 = 300nm, g = 60nm. In this stage, signal port is always ON with the input light intensity I0=1x106 V2/m2. When the control ports A and B are both
OFF, the output port is ON. The magnetic field distribution is shown in Fig. 3.29 (a).
The transmission efficiency at the wavelength 1310nm is about 97.3%, as shown in Fig.
3.29 (b). When the control port A is OFF and the control port B is ON, with the input light intensity I1=5x107 V2/m2, the output port is ON. The magnetic field distribution is shown in Fig. 3.30 (a). The transmission efficiency at the wavelength 1310nm is about 96.1%, as shown in Fig. 3.30 (b). When the control port A is ON, with the input light intensity I1=5x107 V2/m2 and the control port B is OFF, the output port is ON. The magnetic field distribution is shown in Fig. 3.31 (a). The transmission efficiency at the wavelength 1310nm is about 96.2 %, as shown in Fig. 3.31 (b). When both the control ports A and B are ON, with the input light intensity I1=5x107 V2/m2, the output port is OFF. The magnetic field distribution is shown in Fig.3.32 (a). The transmission efficiency at the wavelength 1310nm is about 0.002% as shown in Fig.3.32 (b). The truth table and the transmission efficiency are shown in Tab. 3.8.
3.3.6. XOR Logic gate
Finally, we use the proposed plasmonic waveguide structure with eight-disk resonators filled with a Kerr-type nonlinear material to design an XOR logic gate, as shown in Fig. 3.8. The parameters of the proposed structure are chosen R1 = 295 nm, R2
= 290nm, R3 = 265 nm, R4 = 260 nm, h = 100 nm, w = 50 nm, w1 = 20 nm, w2 = 30 nm, d2 = 240nm, L1 = 400nm, L2 = 300nm, g = 60nm. In this stage, signal port is always ON with the input light intensity I0=1x106 V2/m2. When the control ports A and B are both OFF, the output port is OFF. The magnetic field distribution is shown in Fig. 3.33 (a).
The transmission efficiency at the wavelength 1310nm is about 0.002% as shown in Fig.
3.33 (b). When the control port A is OFF and the control port B is ON, with the input
light intensity I1=6x107 V2/m2, the output port is ON. The magnetic field distribution is shown in Fig. 3.34 (a). The transmission efficiency at the wavelength 1310nm is about97.3%, as shown in Fig. 3.34 (b). When the control port A is ON, with the input light intensity I1=6x107 V2/m2 and the control port B is OFF, the output port is ON. The magnetic field distribution is shown in Fig. 3.35 (a). The transmission efficiency at the wavelength 1310nm is about 96.8 %, as shown in Fig. 3.35 (b). When both the control ports A and B are ON, with the input light intensity I1=6x107 V2/m2, the output port is OFF. The magnetic field distribution is shown in Fig.3.36 (a). The transmission efficiency at the wavelength 1310nm is about 0.002%, as shown in Fig.3.36 (b). The truth table and the transmission efficiency are shown in Tab. 3.9.