Phase-change material-assisted all-optical temporal differentiator.

This paper proposes a novel microring resonator (MRR)-based all-optical tuning temporal differentiator (DIFF). Specifically, the DIFF uses nonvolatile phase-change material GeSbTe (GST) to achieve low energy consumption and high-speed optical control of the state of the MRR, avoiding the traditional electro-optic (EO) and thermo-optic (TO) tuning designs. By changing the crystallinity of GST to changing the coupling regimes of the MRR, a broad range for the differentiation order α, i.e., 0.47-1.64 can be realized. The intensity response and phase response of the GST-assisted MRR, and normalized intensity in the output of the temporal DIFFs for Gaussian optical pulses have been obtained by simulation. Furthermore, input pulse width and detuning influence on the differentiation order and output deviation are discussed. Finally, our structure can effectively reduce the chip area and power consumption compared with the traditional EO and TO tuning designs.