Compact and broadband 2 × 2 optical switch based on hybrid plasmonic waveguides and curved directional couplers

Abstract

In this paper, a compact, broadband, and CMOS compatible 2 × 2 optical switch based on hybrid plasmonic waveguides (HPWs) and curved directional coupler is presented. The proposed coupler consists of a combination of straight and curved hybrid plasmonic waveguides. By using the ability of HPWs for confining the light wave in a sub-wavelength scale and the curved structure to decrease the wavelength dependence of the directional coupler, a 3 dB power splitter with a 3 dB ± 0.5 bandwidth of about 410 nm and a footprint of 7.6 µ m × 2 µ m is achieved. By exploiting this optimal power splitter in a Mach–Zehnder interferometer structure, a 2 × 2 electro-optic switch with a broad bandwidth of 400 nm and a small footprint of 33 µ m × 2.5 µ m is realized, which denotes the widest bandwidth compared to the previously reported similar structures. The three-dimensional finite-difference time-domain simulation results show a switching speed of 0.15 THz for the proposed optical switch, while the extinction ratio, power consumption, and insertion loss are 20 dB, 95.2 fJ/bit, and 4 dB, respectively, at the central wavelength of 1550 nm.

Modeling of a more Compact and Efficient Hybrid Plasmonic Electro-Optic Modulator using 3D finite-difference time-domain (FDTD) algorithm

“…The modulation process involves modifying the refractive index of the active medium, situated between the layers of the MOS waveguide, through forward biasing of the MOS waveguide using an external electrical potential applied between the noble metal layer (positive) and the Si layer (ground), as illustrated in figure (2). Upon applying bias to the MOS waveguide, the effective index of the optical mode shifts, leading to variations in the modal overlap between neighboring waveguides [22][23].…”

Subwavelength silicon photonics for on-chip mode-manipulation

“…For example, an MZI with the assistance of SWG waveguides have been demonstrated for all-optical switching [267][268][269]. When using an SWG waveguide in one arm and a conventional strip waveguide in the other one, an optical path imbalance was produced due to the difference of their effective indices.…”

Highly Transmission Efficiency of Optoelectronic Devices Using Active Hybrid Plasmonic Coupler

“…As can be seen from the figure, the logic operation of the gate depends mainly on the control signal, taking into account that the input signal is always present. Figure (15) shows the performance of the logic gate by using the transmission value, which is calculated from equation ( 8) When the control signal is on the 4-volt mode, or in other words, the control unit is in the BAR state, this means that the input represents the Logic 1 and it is output in this case is Logic 0. While when the control signal is in the 0-volt mode, or in other words, the control unit is in the CROSS state, this means that the income represents Logic 0, and the output in this case is Logic 1.…”

“…Transparent conductive oxides are oxide' semiconductors that have been utilized in optoelectronic structures because of their strong nonlinear response, electrically-tunable permittivity, and fast energy transfer [15][16]. Indium tin oxide (ITO) was chosen for this task due to its unity-strong index tenability.…”