A BaTiO₃-Based Electro-Optic Pockels Modulator Monolithically Integrated on an Advanced Silicon Photonics Platform

Abstract

To develop a new generation of high-speed photonic modulators on silicon-technology-based photonics, new materials with large Pockels coefficients have been transferred to silicon substrates. Previous approaches focus on realizing stand-alone devices on dedicated silicon substrates, incompatible with the fabrication process in silicon foundries. In this work, we demonstrate monolithic integration of electro-optic modulators based on the Pockels effect in barium titanate (BTO) thin films into the back-end-of-line of a photonic integrated circuit (PIC) platform. Molecular wafer bonding allows fully PIC-compatible integration of BTO-based devices and is, as shown, scalable to 200 mm wafers. The PICintegrated BTO Mach-Zehnder modulators outperform conventional Si photonic modulators in modulation efficiency, losses, and static tuning power. The devices show excellent V π L (0.2 Vcm) and V π Lα (1.3 VdB), work at high speed (25 Gbps), and can be tuned at low-static power consumption (100 nW). Our concept demonstrates the possibility of monolithic integration of Pockels-based electro-optic modulators in advanced silicon photonic platforms.

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

“…These developments bode well for the realization of practical modulators based on BTO on Si. Days before the submission of this review, Abel's IBM group has scaled‐up this work and demonstrated monolithic integration of the wafer‐bonded BTO onto 200 mm Si wafers …”

Advances in Silicon Quantum Photonics

“…BTO, with its ultra-high Pockels coefficient, is another attractive option, and BTO-Si hybrid modulators have been demonstrated up to 50 GHz (Fig. 1k) [71], [134], and at This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication.…”

Microwave Photonic ICs for 25 Gb/s Optical Link Based on SiGe BiCMOS Technology

“…Also, there are technological solutions of the V π • L decreasing up to 0.74 V cm by using the special doping profiles, while maintaining high speed performance of 48 GHz [20]. In [21], the lowest value of V π • L (0.2 V•cm) at 25 Gbps was reached with the help of barium titanate (BTO) thin film integrated into silicon photonic process. In order to define the length of the modulator segment, the test (prototype) MZM is designed and produced ( Figure 4).…”