Ring resonator modulators reach high modulation efficiencies, are very compact and can be electrically driven as lumped elements. However, their limited optical bandwidth requires temperature stabilization, limiting their power efficiency. A novel ring assisted Mach-Zehnder modulator (MZM) aggressively reduces power consumption. Moreover, an integration scheme passively sets the 3 dB point during attachment of the input fiber relative to a multimode grating coupler used as the first splitter

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... ment of the interferometer. Straight phase shifters are replaced by arrays of highly overcoupled resonators maintaining a sufficiently high finesse and a substantial resonant enhancement while minimizing the excess losses at the resonator to waveguide junctions. A large resonance bandwidth compatible with thermal operation over 50 °C without dynamic compensation is obtained together with a factor larger than four in the reduction of power consumption relative to a conventional MZM.