We demonstrate a silicon electronic–photonic integrated 25 Gb/s nonreturn-to-zero transmitter that includes driver circuits, depletion-type Si ring modulator, Ge photodetector, temperature sensor, on-chip heater, and temperature controller, all monolithically integrated on a 0.25 μm photonic BiCMOS technology platform. The integrated transmitter successfully provides stable and optimal 25 Gb/s modulation characteristics against external temperature fluctuation.

We present an accurate, easy-to-use large-signal SPICE circuit model for depletion-type silicon ring modulators (Si RMs). Our model includes both the electrical and optical characteristics of the Si RM and consists of circuit elements whose values change depending on modulation voltages. The accuracy of our model is confirmed by comparing the SPICE simulation results of 25 Gb/s non-return-to-zero (NRZ) modulation with the measurement. The model is used for performance optimization of monolithically integrated Si photonic NRZ and pulse-amplitude-modulation 4 transmitters in the standard SPICE circuit design environment.

We demonstrate an integrated Si optical single-sideband (OSSB) modulator composed of a parallel dual-ring modulator (PDRM) and a quadrature hybrid coupler (QHC). Both the PDRM and the QHC are carefully designed for 30 GHz opearation, and their operations are verified by measurement. The Si OSSB modulator successfully generates a single sideband with larger than 15 dB suppression of the undesired sideband.