Breaking the Energy-Bandwidth Limit of Electrooptic Modulators: Theory and a Device Proposal

In this paper, we quantitatively analyzed the tradeoff between energy per bit for switching and modulation bandwidth of classical electrooptic modulators. A formally simple energy-bandwidth limit (10) is derived for electrooptic modulators based on intracavity index modulation. To overcome this limit, we propose a dual cavity modulator device which uses a coupling modulation scheme operating at high bandwidth (>200 GHz) not limited by cavity photon lifetime and simultaneously features an ultralow switching energy of 0.26 aJ, representing over three orders of magnitude energy consumption reduction compared to state-of-the-art electrooptic modulators.