High speed carrier-depletion modulators with 14V-cm V_πL integrated on 025μm silicon-on-insulator waveguides

TLDR

The modulator is a Mach‑Zehnder interferometer fabricated on 0.25 µm SOI waveguides with offset lateral PN junctions. The device achieves an ultralow VπL of 1.4 V‑cm, a 3 dB bandwidth exceeding 12 GHz, and a clear eye diagram at 12.5 Gb/s, demonstrating high‑speed performance.

Abstract

We demonstrate a very efficient high speed silicon modulator with an ultralow pi-phase-shift voltage-length product V(pi)L = 1.4V-cm. The device is based on a Mach-Zehnder interferometer (MZI) fabricated using 0.25microm thick silicon-on-insulator (SOI) waveguide with offset lateral PN junctions. Optimal carrier-depletion induced index change has been achieved through the optimization of the overlap region of carriers and photons. The 3dB bandwidth of a typical 1mm long device was measured to be more than 12GHz. An eye-diagram taken at a transmission rate of 12.5Gb/s confirms the high speed capability of the device.