It is a Mach–Zehnder modulator with two gold electrodes on a substrate facing each other across 10nm wide slot 10µm long.
Inside the slot is a substance only described as a ‘non-linear organic electro-optic material’, and at opposite ends of the slot are silicon waveguides that are finally coupled to the input and output optical fibres.
Modulation is through variation of refractive index as the electric field changes – the Pockels effect.
Fed with 1,545nm light, the modulator worked continuously across 1MHz to 1.14THz – with eight different signal generators needed to test performance from end to end. 3dB roll-off was at 997GHz.
“This achievement confirms the potential of plasmonic modulators to bring THz frequencies to photonic integrated circuits,” said researcher Yannik Horst.
(PICs). For many years, its capability beyond 500 GHz was just theory.” Building on the results of Burla et al. (APL Photonics, 2019), measurements up to 1.1 THz are now possible thanks to an optimized modulator design and improved electronics.
These devices open up applications in THz imaging, sensing and wireless communications,” said Polariton CEO Wolfgang Heni.
Results are available in the Optical paper ‘Ultra-wideband MHz to THz plasmonic EO modulator‘.
Image: Johannes Grewer Polariton Technologies
