Ultra-compact nonvolatile plasmonic phase change modulators and switches with dual electrical–optical functionality

Abstract

Programmable photonic integrated circuits (PICs) are the foundation of on-chip optical technologies, with the optical modulators being one of the main building blocks of such programmable PICs. However, most of the available modulators suffer from high power consumption, low response time, and large footprint. Additionally, they show a large resistance modulation; thus, they require high switching voltage. In consequence, they operate much above CMOS-compatible voltages of 1.2 V and with high insertion losses. Furthermore, the state and information they carry are lost once the power is turned off—so, they are volatile. Thus, realizing modulators and phase shifters that overcome all those problems still remains a challenge. To overcome some of those limitations, the nonvolatile phase change materials implemented in the plasmonic structures are proposed that can offer many advantages as result of high electric field interaction with nonvolatile materials. Consequently, novel plasmonic nonvolatile switches proposed here can operate by phase modulation, absorption modulation, or both and under zero-static power. For the first time, the nonvolatile phase modulator is proposed that requires only 230 nm long active waveguide to attain full π phase delay with an insertion loss below even 0.12 dB. Simultaneously, under the requirements, it can operate as an amplitude modulator with an extinction ratio exceeding 2.2 dB/μm while the insertion losses are kept below 0.185 dB/μm. Furthermore, the heating mechanism can be based on the external heaters, internal heaters, electrical (memory) switching, or optical switching mechanism, which provide a lot of flexibility in terms of a design and requirements.