Charge–Discharge Digital/Analog Microring Modulator With No Intrinsic Speed Limitation

Abstract

Coupling modulation in microring resonators substantiates a compact and high bandwidth silicon photonics modulation scheme. In this letter, we present large-signal analysis elucidating that the main drawback of this scheme is the cavity energy decay during analog and digital modulation. Then, we propose a solution, charge-discharge configuration, having two optical inputs to compensate for the power drainage from the ring. This new modulator exhibits RF-bandwidth and extinction ratio not limited by Q-factor with virtually unlimited modulation bandwidth. We emphasize an Orthogonal Frequency-Division Multiplexing (OFDM) modulation format at 50 GHz and show it is feasible on a silicon photonics platform.

A high-speed electro-optic triple-microring resonator modulator

“…In order to break the photon lifetime limitation, coupling intensity modulations have been proposed in the past years 12 – 15 . It has been theoretically predicted that the microring retains constant optical power in the cavity, while the cavity releases the light by tuning the coupling coefficient between the resonator and waveguide 13 . Since the modulator is tuned by the coupling coefficient instead of the intracavity index, the modulation frequency can be improved beyond the cavity photon lifetime limitation.…”