Design of an all-optical plasmonic modulator for two micrometer waveband

Abstract

In order to meet up the future demand of bandwidth, optical communication wavelength have to be shifted to new wavelength of 2 µm in future. In this study, an all-optical PCM based reflection modulator for upcoming 2 µm communication band have been proposed. The reflectance of the structure can be manipulated by altering the phase of GST by employing optical or electrical stimuli. For designing all optical modulator, optical stimuli has been used to change the phase of GST. Numerical investigation reveals that the nanogear array based structure exhibits a conspicuous changeover from ∼ 99% absorption to very poor interaction with the operating light depending on the switching states of the GST, ending up with 85% modulation depth and only 0.58 dB insertion loss. Due to noticeable differences in optical responses of GST material, a high extinction ratio of 28 dB, a commendable FOM of 49, and 25 MHz switching speed can be achieved which is so far the best modulation performance in this wavelength window. In addition, real-time tracking of the reflectance during phase transition manifests highspeed switching expending low energy per cycle, on the order of sub-nJ. Moreover, we have also proposed another Vanadium di-oxide based modulator which can solve the endurability issue of GST based modulator. This design exhibits a promising result like a large modulation depth of 80%, a high extinction ratio of 15 dB, low switching power of 0.12 pJ/nm2 and 15.8 MHz switching frequency. Hence, given their overall performance, the two devices will be a paradigm shift for the optical modulators for upcoming 2 µm communication technology.