MEMS-enabled silicon photonic integrated devices and circuits

Photonic integrated circuits have seen a dramatic increase in complexity over the past decades. This development has been spurred by recent applications in datacenter communications and enabled by the availability of standardized mature technology platforms. Mechanical movement of wave-guiding structures at the micro- and nanoscale provides unique opportunities to further enhance functionality and to reduce power consumption in photonic integrated circuits. We here demonstrate integration of MEMS-enabled components in a simplified silicon photonics process based on IMEC's Standard iSiPP50G Silicon Photonics Platform and a custom release process

Compact broadband suspended silicon photonic directional coupler

Directional couplers are extensively used in photonic integrated circuits as basic components for efficient on-chip photonic signal routing. Conventionally, directional couplers are fully encapsulated in the technology's waveguide cladding material. In this Letter, we demonstrate a compact broadband directional coupler, fully suspended in air and exhibiting efficient power coupling in the cross state. The coupler is designed and built based on IMEC's iSiPP50G standard platform, and hydrofluoric (HF) vapor-etching-based post-processing allows to release the freestanding component. A low insertion loss of 0.5 dB at lambda = 1560 nm and a 1 dB bandwidth of 35 nm at lambda = 1550 nm have been confirmed experimentally. With a small footprint of 20 mu m x 30 mu m and high mechanical stability, this directional coupler can serve as a basic building block for large-scale silicon photonic microelectromechanical systems (MEMS) circuits. (C) 2020 Optical Society of Americ

Non-contact polishing of single crystal diamond by ion beam etching

We propose a non-contact surface finishing method for brittle substrates by ion beam etching and we experimentally demonstrate polishing of (100) single crystal diamond surface. We model and simulate the polishing process, and verify the results experimentally by monitoring individual defects during the surface treatment. Rapid flattening of scratches and digs, as typically present on brittle substrates after mechanical polishing, is observed: trench depth is typically removed by 95% in less than 30 min. The polishing method relies on physical bombardment of the substrate surface with accelerated inert gas ions, rendering it highly versatile and applicable to a wide variety of materials

MEMS for Photonic Integrated Circuits

The field of microelectromechanical Systems (MEMS) for photonic integrated circuits (PICs) is reviewed. This field leverages mechanics at the nanometer to micrometer scale to improve existing components and introduce novel functionalities in PICs. This review covers the MEMS actuation principles and the mechanical tuning mechanisms for integrated photonics. The state of the art of MEMS tunable components in PICs is quantitatively reviewed and critically assessed with respect to suitability for large-scale integration in existing PIC technology platforms. MEMS provide a powerful approach to overcome current limitations in PIC technologies and to enable a new design dimension with a wide range of applications

Low-voltage silicon photonic MEMS switch with vertical actuation

We present a vertically movable silicon photonic MEMS switch realized in IMEC's standard silicon photonics platform followed by a dedicated postprocessing for MEMS release. The device has six optical ports, which enable four switching configurations with a safe electrical isolation of the switch's actuator. A low actuation voltage of 3.75 V is required to efficiently switch the optical signal from the drop port to the through port of the device. The device exhibits port extinctions of 16 dB and 26 dB at its OFF and ON states, respectively. With an insertion loss of 35 nm, this component paves the way for low-power scalable circuits in MEMS-enabled silicon photonics

Silicon photonic MEMS add-drop filter

We demonstrate a compact add-drop filter based on a MEMS ring resonator implemented in IMEC's iSiPP50G silicon photonics platform. The device exhibits a port extinction of 20 dB and a port isolation of > 50 dB, upon actuation range of 0 V to 27 V

Neuronal growth on high-aspect-ratio diamond nanopillar arrays for biosensing applications

Monitoring neuronal activity with simultaneously high spatial and temporal resolution in living cell cultures is crucial to advance understanding of the development and functioning of our brain, and to gain further insights in the origin of brain disorders. While it has been demonstrated that the quantum sensing capabilities of nitrogen-vacancy (NV) centers in diamond allow real time detection of action potentials from large neurons in marine invertebrates, quantum monitoring of mammalian neurons (presenting much smaller dimensions and thus producing much lower signal and requiring higher spatial resolution) has hitherto remained elusive. In this context, diamond nanostructuring can offer the opportunity to boost the diamond platform sensitivity to the required level. However, a comprehensive analysis of the impact of a nanostructured diamond surface on the neuronal viability and growth was lacking. Here, we pattern a single crystal diamond surface with large-scale nanopillar arrays and we successfully demonstrate growth of a network of living and functional primary mouse hippocampal neurons on it. Our study on geometrical parameters reveals preferential growth along the nanopillar grid axes with excellent physical contact between cell membrane and nanopillar apex. Our results suggest that neuron growth can be tailored on diamond nanopillars to realize a nanophotonic quantum sensing platform for wide-field and label-free neuronal activity recording with sub-cellular resolution

Flip chip packaging of digital silicon photonics MEMS Switch for cloud computing and data centre

We report on the flip chip packaging of Micro-Electro-Mechanical System (MEMS)-based digital silicon photonic switching device and the characterization results of 12 × 12 switching ports. The challenges in packaging N2 electrical and 2N optical interconnections are addressed with single-layer electrical redistribution lines of 25 µm line width and space on aluminum nitride interposer and 13° polished 64-channel lidless fiber array (FA) with a pitch of 127 µm. 50 µm diameter solder spheres are laser-jetted onto the electrical bond pads surrounded by suspended MEMS actuators on the device before fluxless flip-chip bonding. A lidless FA is finally coupled near-vertically onto the device gratings using a 6-degree-of-freedom (6-DOF) alignment system. Fiber-to-grating coupler loss of 4.25 dB/facet, 10–11 bit error rate (BER) through the longest optical path, and 0.4 µs switch reconfiguration time have been demonstrated using 10 Gb/s Ethernet data stream

Wafer-level vacuum sealing for packaging of silicon photonic MEMS

Silicon (Si) photonic micro-electro-mechanical systems (MEMS), with its low-power phase shifters and tunable couplers, is emerging as a promising technology for large-scale reconfigurable photonics with potential applications for example in photonic accelerators for artificial intelligence (AI) workloads. For silicon photonic MEMS devices, hermetic/vacuum packaging is crucial to the performance and longevity, and to protect the photonic devices from contamination. Here, we demonstrate a wafer-level vacuum packaging approach to hermetically seal Si photonic MEMS wafers produced in the iSiPP50G Si photonics foundry platform of IMEC. The packaging approach consists of transfer bonding and sealing the silicon photonic MEMS devices with 30 μm-thick Si caps, which were prefabricated on a 100 mm-diameter silicon-on-insulator (SOI) wafer. The packaging process achieved successful wafer-scale vacuum sealing of various photonic devices. The functionality of photonic MEMS after the hermetic/vacuum packaging was confirmed. Thus, the demonstrated thin Si cap packaging shows the possibility of a novel vacuum sealing method for MEMS integrated in standard Si photonics platforms

Submicrometer Hall devices fabricated by focused electron-beam-induced deposition

Hall devices having an active area of about (500 nm)(2) are fabricated by focused electron-beam-induced deposition. The deposited material consists of cobalt nanoparticles in a carbonaceous matrix. The realized devices have, at room temperature, a current sensitivity of about 1 V/AT, a resistance of a few kilo-ohms, and can be biased with a maximum current of about 1 mA. The room-temperature magnetic field resolution is about 10 muT/Hz(1/2) at frequencies above 1 kHz