Speaker: Aditya Arya (ee13s025)
Silicon photonics is the first choice while designing all-optical switches, due to its low-loss and high transmission bandwidth. The footprint of the device is of the order of the wavelength in that medium (diffraction limit). But, one of the main limitations of integrating the silicon photonic technology with most ubiquitous CMOS technology (for integrated circuit) is the dimensionality mismatch. Fortunately, in the last decades it has been shown that light signals can be guided at the dimension well below its diffraction limit through the resonance coupling of the EM wave in dielectric and electron cloud oscillation in metal at the dielectric-metal interface. This phenomenon is called as surface plasmon Polariton (SPP) and it allowed researchers to couple light energy into plasmonic oscillations and vice-versa. The main advantage is that the dimension mismatch problem is eliminated and allowing seamless integration with current CMOS technologies, to realize all-optical switches. Unfortunately, the SPP waves are more susceptible to damping, which puts an upper limit on the propagation length of light. In this effort, we demonstrate a realizable plasmonic switch structure with external RF signal excitation (representing user data) using plasmonic as well as photonic waveguide.
In the light of above, we have designed two types of plasmonic switches at optical frequency using (a) Ring Resonators (RR), and (b) Mach-Zehnder Interferometer (MZI) and compared their performances. In this work, we have used the linear electro-optic effect (Pockel’s effect) for switching mechanism of light and we have also estimated the packet switching rate of the switch. We have successfully shown the switching behavior of the switch using combined electric and optical interface in COMSOL multiphysics. Our main goal here is to design an optimal switch and optimize its performances. The performance measures of the switch considered here are (a) signal transit time (switching speed), (b) foot-print, and (c) energy consumption.