CMOS-Compatible Si-Ring-Assisted Mach–Zehnder Interferometer With Internal Bandwidth Equalization

Abstract

We demonstrate, to the best of our knowledge, the first electrooptic ring-assisted Mach-Zehnder interferometric (RAMZI) modulator in a CMOS-compatible technology. The RAMZI modulator is manufactured on a CMOS-compatible platform and entirely fabricated in a commercial CMOS foundry. We demonstrate a small-signal 3-dB bandwidth >15 GHz in a silicon-based carrier-depletion modulator with a 2-V·cm <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V¿L</i> product, which is approximately two times smaller than previously reported. We achieved a 10-Gb/s eye diagram with a 2-dB extinction ratio using a 4-V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p-p</sub> drive in a modulator with a 680-¿m optic/RF interaction region. In addition, we demonstrate internal bandwidth equalization within the tunable CMOS-compatible RAMZI modulator, and discuss the optical carrier and modulation sideband response, and relaxation characteristics that lead to this behavior within resonant modulators.