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Proceedings Paper

Power-efficient lumped-element meandered silicon Mach-Zehnder modulators
Author(s): S. Sharif Azadeh; J. Nojić; A. Moscoso-Mártir; F. Merget; J. Witzens

Paper Abstract

Driving electro-optic modulators in lumped-element (LE) configuration allows for small footprint, reduced power consumption, and improved high-speed performance. The main shortcoming of conventional rectilinear LE modulators are the required high drive-voltages, resulting from their shortened phase-shifters. To address this, we introduce a Mach- Zehnder modulator with meandered phase shifters (M-MZM), which can be driven in LE configuration, while keeping the optical phase shifter length in the same order as traveling-wave modulators (TW-MZMs). A design limitation that needs to be taken into account consists in the optical transit time of the device, that limits the overall electro-optic bandwidth. First, we review the overall power consumption improvement as well as the bandwidth enhancement in LE modulators compared to TW-MZMs, also taking the driver output impedance and parasitics from wire- or bump-bonds into account. Then, we report on the design, implementation, and experimental characterization of carrier-depletion based M-MZMs fabricated on silicon-on-insulator (SOI) wafers using standard CMOS-compatible processes. The fabricated M-MZMs, provided with low (W1), moderately (W2) and highly (W3) doped junctions, require 9.2 Vpp, 5.5 Vpp, and 3.7 Vpp for full extinction, with optical insertion losses of 5 dB, 6.3 dB and 9.1 dB. For all three M-MZMs, open eye diagrams are recorded at 25 Gb/s using a 50 Ω driver and termination. For unterminated M-MZMs, higher data rates could be achieved, provided that a low output impedance driver be wire- or bump-bonded to the modulators. Finally, we compare the power consumption of the M-MZMs with TW-MZMs and show that the M-MZMs feature a 4X reduced power consumption at 25 Gb/s.

Paper Details

Date Published: 26 February 2020
PDF: 11 pages
Proc. SPIE 11285, Silicon Photonics XV, 112850C (26 February 2020); doi: 10.1117/12.2544735
Show Author Affiliations
S. Sharif Azadeh, RWTH Aachen Univ. (Germany)
Max Planck Institute of Microstructure Physics (Germany)
J. Nojić, RWTH Aachen Univ. (Germany)
A. Moscoso-Mártir, RWTH Aachen Univ. (Germany)
F. Merget, RWTH Aachen Univ. (Germany)
J. Witzens, RWTH Aachen Univ. (Germany)

Published in SPIE Proceedings Vol. 11285:
Silicon Photonics XV
Graham T. Reed; Andrew P. Knights, Editor(s)

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