100 GHz silicon–organic hybrid modulator

Electro-optic modulation at frequencies of 100 GHz and beyond is important for photonic-electronic signal processing at the highest speeds.To date,however,only a small number of devices exist that can operate up to this frequency.In this study,we demonstrate that this frequency range can be addressed by nanophotonic,silicon-based modulators.We exploit the ultrafast Pockels effect by using the silicon–organic hybrid(SOH)platform,which combines highly nonlinear organic molecules with silicon waveguides.Until now,the bandwidth of these devices was limited by the losses of the radiofrequency(RF)signal and the RC(resistor-capacitor)time constant of the silicon structure.The RF losses are overcome by using a device as short as 500 μm,and the RC time constant is decreased by using a highly conductive electron accumulation layer and an improved gate insulator.Using this method,we demonstrate for the first time an integrated silicon modulator with a 3dB bandwidth at an operating frequency beyond 100 GHz.Our results clearly indicate that the RC time constant is not a fundamental speed limitation of SOH devices at these frequencies.Our device has a voltage–length product of only V_(π)L=11 V mm,which compares favorably with the best silicon-photonic modulators available today.Using cladding materials with stronger nonlinearities,the voltage–length product is expected to improve by more than an order of magnitude.

Femtojoule electro-optic modulation using a silicon– organic hybrid device

Energy-efficient electro-optic modulators are at the heart of short-reach optical interconnects,and silicon photonics is considered the leading technology for realizing such devices.However,the performance of all-silicon devices is limited by intrinsic material properties.In particular,the absence of linear electro-optic effects in silicon renders the integration of energy-efficient photonic–electronic interfaces challenging.Silicon–organic hybrid(SOH)integration can overcome these limitations by combining nanophotonic silicon waveguides with organic cladding materials,thereby offering the prospect of designing optical properties by molecular engineering.In this paper,we demonstrate an SOH Mach–Zehnder modulator with unprecedented efficiency:the 1-mm-long device consumes only 0.7 fJ bit^(-1) to generate a 12.5 Gbit s^(-1) data stream with a bit-error ratio below the threshold for hard-decision forward-error correction.This power consumption represents the lowest value demonstrated for a non-resonant Mach–Zehnder modulator in any material system.It is enabled by a novel class of organic electro-optic materials that are designed for high chromophore density and enhanced molecular orientation.The device features an electro-optic coefficient of r33<180 pm V^(-1) and can be operated at data rates of up to 40 Gbit s^(-1).