Ultra-High Electro-Optic Activity Demonstrated in a Silicon-Organic Hybrid (SOH) Modulator

Efficient electro-optic (EO) modulators crucially rely on advanced materials that exhibit strong electro-optic activity and that can be integrated into high-speed phase shifter structures. In this paper, we demonstrate record-high in-device EO coefficients of up to r₃₃ = 390 pm/V achieved in a silicon-organic hybrid (SOH) Mach-Zehnder Modulator (MZM) using the EO chromophore JRD1. This is the highest material-related in-device EO coefficient hitherto achieved in a Pockels-type modulator at any operating wavelength. The π-voltage of the 1.5 mm-long device amounts to 210 mV, leading to a voltage-length product of UπL = 320 Vµm – the lowest value reported for MZM based on low-loss dielectric waveguides. The viability of the devices is demonstrated by generating error-free on-off-keying (OOK) signals at 40 Gbit/s at a drive voltage as low as 140 mVpp. We expect that efficient high-speed EO modulators will not only have major impact in the field of optical communications, but will also open new avenues towards ultra-fast photonic-electronic signal processing.