Fig. 4: Back-end integration of GSS4T1 with straight waveguide for multilevel intensity modulation. | Nature Communications

Fig. 4: Back-end integration of GSS4T1 with straight waveguide for multilevel intensity modulation.

From: Monolithic back-end-of-line integration of phase change materials into foundry-manufactured silicon photonics

Fig. 4

a Optical constant of the GSS4T1 film on a silicon substrate before and after annealing. b Microscope image of the photonic attenuator. Measured spectra for multilevel amorphization (c) and crystallization (d). For amorphization, 500-ns pulses with amplitudes ranging from 7.50 V to 8.80 V with an interval of 0.05 V were employed, excluding values of 7.55 V, 7.60 V and 7.65 V, but including 8.02 V. For crystallization, 100-ms pulses ranging in amplitude from 1.90 V to 2.25 with interval of 0.01 V were applied, excluding values of 2.21 V, 2.22 V, 2.23 V and 2.24 V. e Multilevel crystallization induced by applying PVDFA. The inset shows the enlarged gradual crystallization. f Fifteen hundred reversible switching events of the photonic attenuator. Arbitrary state configurations induced by various amplitudes (g) and durations (h). All the transmittance changes were all measured at 1550 nm.

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