Reconfigurable optical gates control power and phase in programmable photonic circuits. However, state-of-the-art optical gates are power-hungry due to using heaters and large due to using Mach-Zehnder Interferometers. Here, we demonstrate a compact low-power optical gate based on a silicon photonic MEMS dual-drive directional coupler.

In large interferometric circuits on SOI-platforms a high number of phase tuners is required to control the flow of light. Furthermore, reconfigurable circuits rely on the control of the phase in each arm of a balanced Mach-Zehnder interferometer (MZI) to create a 2×2 coupler with full control on the coupling and phase difference between the output ports [1]. Consequently, such circuits require a large amount of phase shifters densely integrated on the chip surface. To enable this, each phase shifter should have a 2π tuning range at a low voltage to ease to co-integration with the driver electronics. Furthermore, as the mesh size increases the insertion loss (IL) should be limited to avoid signal degradation. Since these devices are densely integrated in such circuits, both the footprint and optical length should be as small as possible while avoiding cross-talk between neighbouring devices.

Nanoelectromechanical (NEM) switches have the advantages of zero leakage current, abrupt switching characteristics, and harsh environmental capabilities. This makes them a promising component for digital computing circuits when high energy efficiency under extreme environmental conditions is important. However, to make NEM-based logic circuits commercially viable, NEM switches must be manufacturable in existing semiconductor foundry platforms to guarantee reliable switch fabrication and very large-scale integration densities, which remains a big challenge. Here, we demonstrate the use of a commercial silicon-on-insulator (SOI) foundry platform (iSiPP50G by IMEC, Belgium) to implement monolithically integrated silicon (Si) NEM switches. Using this SOI foundry platform featuring sub-200 nm lithography technology, we implemented two different types of NEM switches: (1) a volatile 3-terminal (3-T) NEM switch with a low actuation voltage of 5.6 V and (2) a bi-stable 7-terminal (7-T) NEM switch, featuring either volatile or non-volatile switching behavior, depending on the switch contact design. The experimental results presented here show how an established CMOS-compatible SOI foundry process can be utilized to realize highly integrated Si NEM switches, removing a significant barrier towards scalable manufacturing of high performance and high-density NEM-based programmable logic circuits and non-volatile memories.

We demonstrate a packaging approach to integrate electrical and optical connections in silicon photonic MEMS, utilizing a custom-designed silicon interposer for routing over 118 electrical connections and a 72 channel fiber array to couple to on-chip fiber grating couplers with minimal transmission loss at 1543 nm wavelength.

Electrostatic MEMS provide low power consumption to programmable photonics. However, the scaling of programmable photonics also requires solutions for circuit monitoring. We demonstrate a MEMS tunable phase monitor with integrated read-out on a foundry platform.

Silicon photonics is an excellent platform for integrated cavity optomechanics due to silicon's high light confinement and favorable mechanical properties. However, optomechanical devices require a vacuum environment to inhibit damping due to air.We present an integrated platform for cavity optomechanics using thermo-compression bonding of silicon caps to provide on-chip vacuum sealing. We demonstrate optomechanical coupling in a vacuum-sealed ring resonator implemented on the platform, either by modulation of the laser power or by using an electrostatic phase shifter in the ring.By enabling optomechanics on a standard platform, we aim to make the technology available to a wider user base.

We present 4-terminal (4-T) silicon (Si) nanoelectronmechanical (NEM) relays fabricated on silicon-oninsulator (SOI) wafers. We demonstrate true 4-T switching behavior with isolated control and signal paths. A pull-in voltage as low as 11.6 V is achieved with the miniaturized design. 4-T NEM relays are a very promising candidate for building ultra-low-power logic circuits since they enable novel circuit architectures to realize logic functions with far fewer devices than CMOS implementations, while also allowing the dynamic power consumption to be reduced by body-biasing.

We present 4-terminal (4-T) silicon (Si) nanoelectron-mechanical (NEM) relays fabricated on silicon-on-insulator (SOI) wafers. We demonstrate true 4-T switching behavior with isolated control and signal paths. A pull-in voltage (Vpi ) as low as 11.6 V is achieved with the miniaturized design. 4-T NEM relays are a very promising candidate for building ultra-low-power logic circuits, since they enable novel circuit architectures to realize logic functions with far fewer devices than CMOS implementations, while also allowing the dynamic power consumption to be reduced by body-biasing.

Integrated nanoelectromechanical (NEM) relays can be used instead of transistors to implement ultra-low power logic circuits, due to their abrupt turn-off characteristics and zero off-state leakage. Further, realizing circuits with 4-terminal (4-T) NEM relays enables significant reduction in circuit device count compared to conventional transistor circuits. For practical 4-T NEM circuits, however, the relays need to be miniaturized and integrated with high-density back-end-of-line (BEOL) interconnects, which is challenging and has not been realized to date. Here, we present electrostatically actuated silicon 4-T NEM relays that are integrated with multi-layer BEOL metal interconnects, implemented using a commercial silicon-on-insulator (SOI) foundry process. We demonstrate 4-T switching and the use of body-biasing to reduce pull-in voltage of a relay with a 300 nm airgap, from 15.8 V to 7.8 V, consistent with predictions of the finite-element model. Our 4-T NEM relay technology enables new possibilities for realizing NEM-based circuits for applications demanding harsh environment computation and zero standby power, in industries such as automotive, Internet-of-Things, and aerospace.

Silicon photonics has emerged as a mature technology that is expected to play a key role in critical emerging applications, including very high data rate optical communications, distance sensing for autonomous vehicles, photonic-accelerated computing, and quantum information processing. The success of silicon photonics has been enabled by the unique combination of performance, high yield, and high-volume capacity that can only be achieved by standardizing manufacturing technology. Today, standardized silicon photonics technology platforms implemented by foundries provide access to optimized library components, including low-loss optical routing, fast modulation, continuous tuning, high-speed germanium photodiodes, and high-efficiency optical and electrical interfaces. However, silicon's relatively weak electro-optic effects result in modulators with a significant footprint and thermo-optic tuning devices that require high power consumption, which are substantial impediments for very large-scale integration in silicon photonics. Microelectromechanical systems (MEMS) technology can enhance silicon photonics with building blocks that are compact, low-loss, broadband, fast and require very low power consumption. Here, we introduce a silicon photonic MEMS platform consisting of high-performance nano-opto-electromechanical devices fully integrated alongside standard silicon photonics foundry components, with wafer-level sealing for long-term reliability, flip-chip bonding to redistribution interposers, and fibre-array attachment for high port count optical and electrical interfacing. Our experimental demonstration of fundamental silicon photonic MEMS circuit elements, including power couplers, phase shifters and wavelength-division multiplexing devices using standardized technology lifts previous impediments to enable scaling to very large photonic integrated circuits for applications in telecommunications, neuromorphic computing, sensing, programmable photonics, and quantum computing.