Abstract
Lithium niobate, dueto its strong electro-optic effect, is an excellent material for high-performance optical modulators. Hybrid integration of thin film lithium niobate and silicon photonic circuits makes it possible to fully exploit potentials of the two material systems. In this paper, we introduce a detailed design procedure for silicon and lithium niobate hybrid integrated modulator using coplanar line electrodes based on Mach-Zehnder interferometer push-pull configuration. A multiphysics model for the crossing section of the modulation section is proposed and analyzed. The results show that optimizing solely the V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">π</sub> L product would not lead to the best 3-dB bandwidth for a certain half-wave voltage due to the increased microwave losses. There exists an optimal ground-signal electrode gap value, which is about 8-9 μm for the present modulator structure. For these optimized structures, 3-dB bandwidths can reach 45 GHz and 137 GHz with half-wave voltages of 2 V and 4 V, respectively, for a lithium niobate waveguide total thickness of 600 nm and a ridge height of 200 nm.
Highlights
Integrated optical modulator is one of the most important devices in optical communications, which converts the information from the electrical signal to the optical carrier
Design Optimization of Silicon and Lithium Niobate Hybrid Integrated TW MZ Modulator on-insulator (SOI) [2], indium phosphide [3], lithium niobate (LN) [1], [4]–[8], and electro-optic (EO) polymer [9] based on different types of structures, e.g. Mach-Zehnder interferometer (MZI) [1], [4], [6], [10], micro-resonator [6], [8]
Since the EO performance of the modulator depends on the cross-sectional structure of the modulation section, which is shown in Fig. 1(b), the optimization of these structural parameters will be discussed in this paper
Summary
Integrated optical modulator is one of the most important devices in optical communications, which converts the information from the electrical signal to the optical carrier. Other optical functional devices, e.g. splitters and routing waveguides, can be fabricated on other matured material platforms, such as SOI or silicon nitride [4], [5], [7], [8], [10], [16]. This type of hybrid integrated modulators has been demonstrated with even better performances, e.g., more stable operating point control, as compared to the ones on monolithic LNOI [17]. These parameters are further optimized for minimizing the driving voltage of the modulator while maintaining a large modulation bandwidth
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
