Silicon optical modulator with shield coplanar waveguide electrodes

A silicon Mach-Zehnder Interferometer (MZI) optical modulator with a shield coplanar waveguide (CPW) transmission line electrode design was demonstrated. This shield-CPW electrode suppresses the signal distortion caused by the parasitic slot-line (SL) mode and improves the electrical bandwidth and the electro-optical (EO) bandwidth. With the shield-CPW electrodes and 5.5 mm-long phase shifters, the silicon MZI optical modulator delivered an EO bandwidth of 30 GHz and a V =3.0 V was achieved at =1310nm. When modulated at 28-Gb/s data rate, it achieved an extinction ratio of 5.66 dB under a driving voltage of V pp=1.3 V, corresponding to a power consumption of 0.8 pJ/bit.