Hybrid electro-optic modulator combining silicon photonic slot waveguides with high-k radio-frequency slotlines
Abstract
Electro-optic (EO) modulators rely on the interaction of optical and electrical signals with second-order nonlinear media. For the optical signal, this interaction can be strongly enhanced using dielectric slot–waveguide structures that exploit a field discontinuity at the interface between a high-index waveguide core and the low-index EO cladding. In contrast to this, the electrical signal is usually applied through conductive regions in the direct vicinity of the optical waveguide. To avoid excessive optical loss, the conductivity of these regions is maintained at a moderate level, thus leading to inherent RC limitations of the modulation bandwidth. In this paper, we show that these limitations can be overcome by extending the slot–waveguide concept to the modulating radio-frequency (RF) signal. Our device combines an RF slotline that relies on B a T i O 3 as a high-k dielectric material with a conventional silicon photonic slot waveguide and a highly efficient organic EO cladding material. In a proof-of-concept experiment, we demonstrate a 1 mm long Mach–Zehnder modulator that offers a 3 dB bandwidth of 76 GHz and a 6 dB bandwidth of 110 GHz along with a small π voltage of 1.3 V ( U π L = 1.3 V m m ). We further demonstrate the viability of the device in a data-transmission experiment using four-state pulse-amplitude modulation (PAM4) at line rates up to 200 Gbit/s. Our first-generation devices leave vast room for further improvement and may open an attractive route towards highly efficient silicon photonic modulators that combine sub-1 mm device lengths with sub-1 V drive voltages and modulation bandwidths of more than 100 GHz.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 09, 2021
- Source ID
- 10.1364/optica.411161
Entities
People
- Ahmed Shariful Alam
- Artem Kuzmin
- Christian Koos
- Delwin L Elder
- Juned Kemal
- Larry Dalton
- Lothar Hahn
- Matthias Lauermann
- S. Ummethala
- Sebastian Randel
- Sree H. Nandam
- Thomas Zwick
- Wolfgang Freude
- Yasar Kutuvantavida
Organizations
- Air Force Office of Scientific Research
- Alfried Krupp von Bohlen und Halbach Foundation
- European Regional Development Fund
- European Research Council
- German Research Foundation
- Horizon 2020
- Karlsruhe Institute of Technology
- National Science Foundation
- University of Washington