Segmented Silicon Modulator With a Bandwidth Beyond 67 GHz for High-Speed Signaling

Abstract

We demonstrate an all-silicon segmented modulator with traveling-wave electrodes, achieving an electro-optic bandwidth beyond 67 GHz and a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_\pi$</tex-math></inline-formula> of 5V. We show that dividing a long optical modulator into shorter segments can help achieve a higher bandwidth without compromising modulation efficiency or optical loss. We analyze the bandwidth limitation due to the delay mismatch between the driving and optical signals. We show that the impact of misalignment of driving delays between segments on the overall bandwidth of the modulator can be described by a finite impulse response filter. Using this modulator, we achieve optical transmission of 120 Gbaud 8-level amplitude shift keying with coherent detection. Taking into account the forward error correction overhead, this yields 336.4 Gb/s net on a single polarization. Our design has the potential for achieving 1 Tb/s using dual-polarization IQ modulation.