Frederic Nabki

• PhD
• Professor (Full) at École de Technologie Supérieure

Optical switches play a critical role in optical communication systems, meeting the growing demand for high-speed data transfer. Among optical switches, micro-opto-electro-mechanical system (MOEMS) switches stand out for their reconfigurability and broadband capability, making them well-suited for applications in data centers. In this article, we p...

In this paper, the design, concept and experimental validation of the performances of a piezoelectric resonant microelectromechanical systems (MEMS) phase comparator is presented. Compared to traditional integrated circuits, the potential benefits of a MEMS phase comparator include a low power consumption, higher sensitivity, higher selectivity and...

Electrothermal actuators are highly advantageous for microelectromechanical systems (MEMS) due to their capability to generate significant force and large displacements. Despite these benefits, their application in reconfigurable conduction line switches is limited, particularly when employing commercial processes. In DC MEMS switches, electrotherm...

We present an interleaver using a Ring-Assisted Mach-Zehnder Interferometer (MZI) where the ring is coupled to one arm of the MZI through a linearly tapered multimode interferometer (MMI), harnessing the advantages of both the MMI coupler and ring assisted MZI to optimize performance. The tapered MMI coupler extends the operational bandwidth of the...

This paper presents a high accuracy air-coupled acoustic rangefinder based on piezoelectric microcantilever beam array using continuous waves. Cantilevers are used to create a functional ultrasonic rangefinder with a range of 0 m up to 1 m. This is achieved through a design of custom arrays. This research investigates various classification techniq...

Modern condition monitoring and industrial fault prediction have advanced to include intelligent techniques, aiming to improve reliability, productivity, and safety. The integration of ultrasonic signal processing with various machine learning (ML) models can significantly enhance the efficiency of industrial fault diagnosis. In this paper, ultraso...

Ultrasonic diagnostics is the earliest way to predict industrial faults. Usually, a contact microphone is employed for detection, but the recording will be contaminated with noise. In this paper, a dataset that contains 10 main faults of pipelines and motors is analyzed from which 30 different features in the time and frequency domains are extracte...

This paper proposes an affordable and fast microwave imaging prototype using a time-domain baseband imaging technique with ultrawideband (UWB) impulse signals. Unlike traditional methods that sample the signal at RF, the signal of the proposed device is self-mixed to be downconverted to baseband, and then sampled using a real-time oscilloscope with...

This article proposes an electrothermal three-degrees-of-freedom (3-DOF) micro-positioner equipped with a waveguide path, which can potentially be used for chip-to-chip alignment in photonic integrated circuits. The micro-positioner provides translational displacements along the x-, y-and z-axes with manageable levels of cross-sensitivity between a...

We present the design and experimental characterization of the first multistage ring-assisted Mach-Zehnder interferometer (RAMZI) lattice (de)multiplexer implemented with silicon nitride optimized for four channels with a spacing of 100 GHz in the L-band. The device comprises two RAMZI stages to provide a sharp box-like response characterized by a...

Reflectors play a pivotal role in silicon photonics since they are used in a wide range of applications, including attenuators, filters, and lasers. This Letter presents six silicon nitride reflectors implemented using the inverse design technique. They vary in footprint, ranging from 4 µm × 3 µm to 4 µm × 8 µm. The smaller device has an average si...

We present the first experimental demonstration of an inverse-designed 5-mode division multiplexer (MDM) in silicon nitride for MEMS-based inter-chip switches. The MDM exhibits high efficiency, wide bandwidth, compactness, robust fabrication, and compatibility with commercial foundry production.

This paper presents the implementation of MEMS to convert Terahertz Time-Domain Spectroscopy (THz-TDS) to the Time-Domain Derivative Spectroscopy (THz-TDDS). This THz signal modulation is achieved without losing the spectroscopy ability for material characterization.

A deep neural network architecture for the automatic sizing of analog circuit components is proposed, with a focus on radio frequency (RF) applications in the 2 to 5 GHz region. It addresses the challenges of the typically small number of examples for network training and the existence of multiple solutions, of which impractical values for integrat...

This work demonstrates a hybrid MEMS actuator platform that combines electrostatic and piezoelectric actuators to displace a suspended MEMS platform along 3 degrees-of-freedom (DOF). The prototype MEMS actuator tested produces maximum displacements of 8.8 $\upmu$ m along the positive X-axis, and 8.5 $\upmu$ m along the negative X-axis, with dig...

We present the concept and design of a novel integrated optical spectrometer able to operate over four different optical bands in the infrared that cover over 900 nm of aggregated bandwidth. The device, named integrated optical four bands spectrometer (IOFBS), consists of a single planar concave grating with 4 inputs waveguides, each corresponding...

This study demonstrates a monolithic 1 x 4 optical switch composed of a planar micro-electro-mechanical system (MEMS) integrated with silicon nitride (SiN) waveguides. The switching motion is induced by an optimized cascaded chevron electrothermal actuator, which produces an analog, precise, and large stroke for low voltages. Nanoscale displacement...

The quality factor of microelectromechanical resonators is a crucial performance metric and has thus been the subject of numerous studies aimed at maximizing its value by minimizing the anchor loss. This work presents a study on the effect of elastic wave reflectors on the quality factor of MEMS clamped–clamped flexural beam resonators. The elastic...

This paper presents a new MEMS varactor that uses repulsive actuation to achieve an ultra-linear capacitance-to-voltage response. The approach proposed involves actuating the moveable electrode away from the fixed electrode, instead of the conventional closing-the-gap direction. This increasing-gap movement reduces the capacitance as the actuation...

Integrated silicon nitride polarizers play a critical role in the design of complex integrated devices such as filters, switches, and large Mach-Zehnder interferometer networks. These devices require precise control of both polarizations on a single circuit. In addition, polarizers are essential to accurately characterize these devices, primarily d...

Alignment is critical for efficient integration of photonic integrated circuits (PICs), and microelectromechanical systems (MEMS) actuators have shown potential to tackle this issue. In this work, we report MEMS positioning actuators designed with the ultimate goal of aligning silicon nitride (SiN) waveguides either to different outputs within a Si...

We demonstrate a compact silicon nitride interferometer which uses waveguides with the same length and different effective indices instead of similar effective indices and different lengths. In such structures there is no need to have waveguide bends. This not only reduces losses but also results in an order of magnitude smaller footprint and thus...

This article presents a multiband low-power and low-complexity impulse radio ultrawideband (IR-UWB) noncoherent receiver. The proposed receiver can be digitally reconfigured in three different modes of operation, including two single-band modes and one concurrent dual-band mode. In the two single-band modes, the proposed envelope detection architec...

Integrating microelectromechanical systems (MEMS) actuators with low-loss suspended silicon nitride waveguides enables the precise alignment of these waveguides to other photonic integrated circuits (PICs). This requires both in-plane and out-of-plane actuators to ensure high-precision optical alignment. However, most current out-of-plane electrost...

An impulse-radio ultra-wideband (IR-UWB) two-way ranging (TWR) system for indoor and harsh environments is described. In the proposed system, a synchronization (sync) word with a specific sequence of UWB impulses and with a particular pulse-position modulation is transmitted from the anchor, and then detected by the tag using a continuous-time sync...

A wideband cascaded receiver and a stacked receiver using an improved clock strategy are proposed to support the software-defined radio (SDR). The improved clock strategy reduces the number of mixer switches and the number of LO clock paths required to drive the mixer switches. This reduces the dynamic power consumption. The cascaded receiver inclu...

In conventional time-domain ultra-wide band (UWB) imaging in the GHz-range, the received signal is sampled and digitized at a very high rate of tens of GHz. This complicates the imaging platform and increases the costs. Instead of digitizing the full signal in time domain, this paper proposes that only a few peak values of the receiver signal and t...

The utilization of MEMS resonators in microelectronics has garnered significant attention, given their crucial role in a multitude of applications, including timing and sensing. Among the various types of resonators, tunable resonators are particularly noteworthy, as they possess the capability of dynamically adjusting their resonant frequency. Acc...

This work presents novel multi degrees-of-freedom (DOF) actuators based on piezoelectric and electrostatic actuation to generate both in-plane and out-of-plane motions, intended to position a suspended optical waveguide for chip-to-chip alignment in photonic integrated circuits. In this context, the mechanical structures of the actuators with a sus...

We demonstrate the first 1x5 electrostatic MEMS optical switch with silicon nitride waveguides that combines analog and digital control. It achieves average insertion losses between 2.2 dB and 5.39 dB for the five switching channels and operates over a wavelength range of 85 nm.

In order to improve the out-of-band interference filtering in the front-end of a wideband radio frequency system, this paper proposes a two-stage low-noise amplifier (LNA) that has three notches in its transfer function. In the proposed LNA, two center-tap inductors are utilized, where the center-tap inductor is modeled as two equal inductors with...

A wideband and low-power RF-to-baseband (BB) current-reuse receiver (CRR) front-end is proposed, and its performance is verified using two matching networks, one with an LC balun and on-chip biasing inductor, CRR1, and another with a differential balun and without on-chip biasing inductor, CRR2, requiring less area. The transimpedance amplifier (TI...

This work describes a novel micromechanical structure capable of producing out-of-plane motion from in-plane forces generated by electrostatic microelectromechanical system (MEMS) actuators. The MEMS actuator is fabricated in a commercial silicon-on-insulator (SOI) MEMS process and is anchored at two distinct locations through a pair of beams with...

A technique to create a temperature insensitive area on a die using an integrated micro-heater and a phase-locked loop (PLL) configuration is described. The proposed PLL configuration employs thermal feedback through the micro-heater to significantly improve the temperature stability of the die area. Two oscillators employed in the PLL act as tempe...

Micro-opto-electro-mechanical systems (MOEMS) based mirrors with a suitable actuation range are often used for optical beam scanning applications. While several MOEMS scanners have been reported, they often have limitations with respect to their range of motion, field of view, mass, size and fabrication cost. In this work, we present a rotary micro...

In this paper the design and experimental validation of the performances of a piezoelectric resonant microelectromechanical systems (MEMS) phase comparator is presented. Compared to the traditional integrated circuits, the potential benefits of a MEMS phase comparator include a low power consumption, higher sensitivity, higher selectivity and impro...

We present a 1 × 3 optical switch based on a translational microelectromechanical system (MEMS) platform with integrated silicon nitride (SiN) photonic waveguides. The fabricated devices demonstrate efficient optical signal transmission between fixed and suspended movable waveguides. We report a minimum average insertion loss of 4.64 dB and a maxim...

This work gives a design perspective on low-power and wideband RF-to-Baseband current-reuse receivers (CRR). The proposed CRR architecture design shares a single supply and biasing current among both LNTA and baseband circuits to reduce power consumption. The work discusses topology selection and a suitable design procedure of the low noise transco...

inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> $N$ -path switching systems using switched-series R-C networks are analyzed in the context of RF receiver front-ends, and it is shown that it is possible to mitigate the need to generate an accurate low power clock at high frequencies by opera...

In this paper, a methodology for increasing the displacement of the membrane in nonlinear transducers is presented. This methodology that relies on pulse shaping is based on the frequency modulation of the excitation signal which in turn results in an amplitude modulation of the displacement of the resonator. The benefits of pulse shaping include t...

We report the first 1 x 3 silicon nitride optical switch using silicon electrostatic MEMS actuator with a 4.97 dB average insertion loss over the 1530 nm to 1580 nm wavelength range.

A low-power and wideband RF-to-baseband (BB) current-reuse receiver (CRR) front-end utilizing both a $1/f$ noise cancellation (NC) technique and an active inductor (AI) is proposed tuned to operate from 1 GHz to 1.7 GHz for L-Band applications, including those that require high modulation bandwidths. The CRR front-end employs a single supply and...

A blocker-tolerant harmonic selection receiver front-end with RF bandwidth of 6.5 GHz to support the fifth-generation (5G) sub-6 GHz band is presented. The proposed N-path switching filter-based receiver employs harmonic recombination blocks at the baseband (BB) to select the desired local oscillator (LO) harmonics and suppress blockers. It is demo...

This article describes a design for a frequency synthesizer architecture based on a phase-locked loop (PLL) for avionic software-defined radio (SDR) applications at up to 9 GHz. Three basic architectural schemes: wide range voltage-controlled oscillator (VCO), single sideband (SSB) mixing, and multiple VCOs can be used to extend the frequency range...

Today, non-invasive imaging has become one of the popular and prevalent methods in medical applications. Ultrasound imaging is a popular imaging modality as it avoids harmless radiation, has low computation cost, can operate in real time and be implemented in low-cost instruments. However, the image quality decreases due to diverse noise sources. I...

We present the analytical modelling and experimental characterization of a new design of silicon nitride tunable bandpass filter based on serially coupled ring resonators assisted Mach-Zehnder interferometer (SR-MZI). SR-MZI filters provide an additional degree of freedom to independently control the bandwidth and shape of the passband as compared...

The engineering of optomechanical systems has exploded over the past decades, with many geometries and applications arising from the coupling of light with mechanical motion. The modulation of electromagnetic radiation in the terahertz (THz) frequency range through optomechanical systems is no exception to this research effort. However, some fundam...

Nonlinear, mechanical microelectromechanical system (MEMS) resonating structures exhibit large displacement and a relatively broad operating bandwidth. These unique features make them particularly of interest for the development of MEMS actuators and sensors. In this work, a mechanical MEMS structure allowing the designer to determine the type of n...

This paper proposes a system in package (SiP) for ultrasonic ranging composed of a 4 × 8 matrix of piezoelectric micromachined ultrasonic transducers (PMUT) and an interface integrated circuit (IC). The PMUT matrix is fabricated using the PiezoMUMPS process and the IC is implemented in the AMS 0.35 µm technology. Simulation results for the PMUT are...

Today’s wireless sensor networks expect to receive increasingly more data from different sources. The Time Slotted Channel Hopping (TSCH) protocol defined in the IEEE 802.15.4-2015 version of the IEEE 802.15.4 standard plays a crucial role in reducing latency and minimizing energy consumption. In the case of convergecast traffic, nodes close to the...

This paper presents a novel operation mechanism for ultrasonic testing in-water. The mechanism employs the surface-tension forces between the water and ultrasonic probe surfaces to cause an elongation (meniscus) of the water column and thus focuses the ultrasonic beam. The proposed meniscus-mode operation mechanism exploits this phenomenon to ampli...

We demonstrate a silicon nitride interferometer with waveguides having different effective indexes instead of lengths to avoid waveguide bends, reduce losses and footprint.

A fully integrated regenerative CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> MEMS sensor using a micro-resonator coated with Linear Polyethylenimine as an adsorbent layer is presented. The pyramidal cantilever micro-resonator used has a resonant frequency of 315.24 kHz with a Q factor of...

This technical note reports a rapid technique to post-process and assemble micro-components onto dies including released movable microstructures. The method is applied to microelectromechanical systems (MEMS) chips that were fabricated using a commercial process, PolyMUMPs from MEMSCAP. It allows the assembly of a micro-polyhedron over released mic...

We present a novel silicon nitride polarization rotator based on a combination of slanted sidewalls and partial removal of the side cladding. It has a conversion efficiency greater than 99% with low fabrication complexity.

We present tunable bandpass optical filters based on serially coupled ring resonators (RRs) coupled to one arm of a Mach-Zehnder interferometer (MZI) with improved tunability and sharper transitions compared to previous MZI-RRs configurations.

In this study, we report on system advancements for an ultrawideband (UWB) microwave radar prototype for early breast cancer detection. We introduce an integrated circuit (IC) pulse radio as a suitable replacement for both a bulky and expensive off-the-shelf pulse generator and a clock. To assess the system's suitability as a breast screening proto...

We propose a novel integrated micro-opto-mechanical-system spectrometer design in a monochromator setup. It consists of a concave grating fabricated in a planar waveguide that is connected to a rotational electrostatic actuator, which enables angular tuning of the grating. The spectrometer covers a wide operational wavelength range (>100 nm), cover...

This article presents the implementation of a novel 22-Gb/s energy-efficient optoelectronic receiver architecture in 65-nm CMOS for short-reach optical communication. The receiver incorporates four sub receivers with a two-bit integrating resettable front-end in each sub receiver. The inputs to two of the four sub receivers are optically delayed by...

We present the design and fabrication of an electrostatic side-drive micromotor that achieves the fastest operating speed reported for a device fabricated using the PolyMUMPS process. High-speed is obtained by optimizing the geometric parameters of the rotor and the stator electrodes, employing techniques to reduce friction in various regions of th...

A high-speed moving average integrator in silicon photonics is demonstrated. The integrator is monolithically fabricated with an optical receiver front-end operating at 1550 nm. The design consists of an optical splitter, an optical low-loss delay line to implement a 400 ps delay between the two received bit streams, two SiGe photodiodes, and a 200...

This paper presents a novel technique for quickly deactivating piezo-electric micromachined ultrasonic transducers (PMUT) in order to increase their potential for acoustic imaging. The proposed PMUT is anchored by four arms and surrounded by two mechanical dampers. The dampers are moved using electrostatic actuators in order to come into contact wi...

The rapid growth of information technology is closely linked to our ability to modulate and demodulate a signal, whether in the frequency or in the time domain. Recent demonstrations of terahertz (THz) modulation involve active semiconductor metamaterial surfaces or use of a grating-based micromirror for frequency offset tuning. However, a wideband...

The comparison between potential coatings for the measurement of CO2 concentration through the frequency shift in micro-resonators is presented. The polymers evaluated are linear polyethylenimine, branched polyethylenimine and reduced graphene oxide (rGO) by microwave reduction with polyethylenimine. The characterization of the coatings was made by...

An ionization sensor based on suspended carbon nanotubes (CNTs) was presented. A suspended CNT beam was fabricated by a low-temperature surface micromachining process using SU8 photoresist as the sacrificial layer. Application of a bias to the CNT beam generated very high non-linear electric fields near the tips of individual CNTs sufficient to ion...

Multi-channel optical receivers clocked at a frequency slower than the data-rate in which different phases are used for each channel are widely used in high data-rate applications. Here, we demonstrate a two-channel optical receiver where both channels share the same clock operating at half of the data-rate frequency. However, instead of using diff...

We propose a simple method to differentiate a THz pulse using a piezoelectric micromachined ultrasonic transducer (PMUT). We demonstrate with simulations that the modulated THz signal after PMUT is proportional to the first-order derivative of the THz pulse.

We propose fabrication tolerant silicon nitride Fabry-Perot optical integrated filters that offer sharp responses with a relatively small footprint. Moreover, micro-heaters implemented on the waveguides can provide tuneability of both the central wavelength and bandwidth.

This paper presents a novel dual-level capacitive microcantilever-based thermal detector that is implemented in the commercial surface micromachined PolyMUMPs technology. The proposed design is implemented side-by-side with four different single-level designs to enable a design-to-design performance comparison. The dual-level design exhibits a rate...

This article describes a high-speed optoelectronic receiver implemented in 65 nm CMOS technology. The receiver utilizes only two clock phases instead of the four conventionally used in a quarter-rate clocking system. This two-clock phase system is enabled by a passive silicon photonic split and delay structure that eliminates the need for a quadrat...