Passively biased resonantly enhanced silicon photonics modulator with high optical bandwidth

Abstract

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 element 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.

Broadband, temperature tolerant and passively biased resonantly enhanced Mach-Zehnder modulators

“…The phase shifters in the MZM are implemented in the form of collectively driven, highly overcoupled RRMs loaded on a common bus waveguide [16]. In the highly overcoupled regime, when the optical carrier is tuned on resonance, the transfer function of a single ring resonator can be given as [22] ! "#$ = !…”