In this paper, we presented a novel electrostatic Roll/Pitch MEMS gyroscope with in-plane drive mode and out-of-plane sense mode. The proposed structure is developed based on a tuning fork gyroscope with decoupled sense mass on each tine that control the sense out-of-plane frequency. A multi-height deep reactive ion etching (DRIE) fabrication process was utilized to achieve and enhance decoupling between the drive and sense modes. We presented our design methodology followed by an analytical and finite element (FEM) model. Our experimental results showed a good match between the analytical model and those obtained experimentally, from the drive and sense oscillation frequencies. Our characterization setup used a custom made application specific integrated circuit (ASIC) for characterization and was able to achieve ARW of 0.2 deg/rt-h, a bias instability 5.5 deg/h, and scale factor non-linearity (SFNL) 156 ppm FS.

Electrostatic parallel plate actuators are common in micro-electro-mechanical systems due to their compatibility with micro-fabrication technology. Parallel plate actuators suffer from an instability problem called the pull-in phenomenon that happens when the applied DC voltage exceeds a certain value called the static pull-in voltage. The value of this critical voltage is important in many applications that depend on parallel plate actuators such as switches and static gas sensors. The fringe field around the edges of the plates could severely affect the performance of the actuator. This paper introduces a new model for the parallel plate actuator to calculate the value of static pull-in voltage. The proposed model considers the fringe field between the two plates. The static pull-in voltage of some PolyMUMPs actuators is practically measured and compared to the simulation results that involve the fringe field effect. The model is simulated using MATLAB to show the influence of that field on the static pull-in voltage. The MATLAB results of the proposed model are validated with ANSYS.

We present an analytical model of an electromagnetic levitation energy harvester and validate it by comparing its result with FEM simulations and experimental measurements. The model is based on dipole-moment approximations of magnetic fields and interaction forces. The level of agreement of both models with measurements is discussed.

Background: Microelectromechanical systems are now one of the fastest growing engineering fields. We introduce a static gas sensor based on PolyMUMPs parallel plate actuators. The sensor exploits the pull-in phenomenon of the parallel plate actuators. The target gas is hydrogen sulfide (H2S), which is a toxic gas and popular in laboratories, factories, and petroleum industry. Aim: Reach a gas sensor in which the gas can easily be detected by a simple electronic circuit using new polymer combinations. Approach: Two concentrations of H2S (40 and 100 ppm) are used to test the ability of the sensor to capture the molecules of the gas. Gas injection process is done in a gas chamber and at ambient conditions (ambient temperature and pressure). Results: The two concentrations were successfully detected by the sensor and the electronic circuit verified the pull-in of the sensor. That was achieved using two different polymers (polypyrrole polymer and copper oxide-tin oxide/polypyrrole). Conclusions: The sensor successively detects H2S gas with 40 and 100 ppm concentrations. Verifying the pull-in of the sensor using a simple detection circuit could help in quickly moving those sensors from prototype to product. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)

This paper goes through the process of designing an electromagnetic Micropower Generator (MPG) to be used for human activity tracking. Finite Element Method (FEM) was employed to simulate the MPG and calculate the power output under different excitations. The MPG was fabricated, tested, and the results compared to the implemented FEM simulations. Good agreement is observed between the two sets of results. The MPG generated 7.7 mW of power under a load of $220\ {\Omega}$ at a natural frequency of 8.9 Hz and acceleration level of 0.24g. The natural frequency is further reduced to 7.2 Hz by removing the top fixed magnet. This achieved higher levels of power output reaching 12 mW at resonance.

Optical phase modulators are essential building components in a wide range of applications, for instance, optical communication systems, tunable lasers, optical phase locked loops, and optical sensors. The production of in-plane MEMS-based optical phase modulator with self-aligned mirrors, actuator, and fiber grooves enables the low cost and easy integration with fiber-based lasers and sensors or photonic microsystems. In this paper, we report an in-plane transmission type MEMS-based optical phase modulator fabricated by deep reactive ion etching technology on a silicon-on-insulator (SOI) substrate. Detailed optical analysis of the MEMS phase modulator considering the diffraction of the single-mode fiber output beam, the asymmetric truncation of the beam by the limited aperture of the micromirrors and the tilt angle of the deeply etched mirrors is presented. The device layer height of the fabricated SOI wafer is 100 mu m, and the sidewalls are etched with verticality that is better than 89.98 degrees. The micromechanical system is characterized experimentally using electrical technique, and the resonance frequency and quality factor are 11.3 kHz and 163, respectively. The MEMS device is integrated into fiber ring laser (FRL) enabling the achievement of low- and high-frequency modulation indices. The frequency modulation of the FRL using the presented phase modulator is supported with numerical analysis and experimental results.

This paper concludes a two-part investigation of a novel architecture for vibration energy harvesting (VEH), the springless VEH. In this part, we study vertical springless electromagnetic VEHs where the direction of motion is aligned with the gravitational field. Experimental results show the existence of three topologies in the response of vertical springless VEHs; linear, single-impact, and double-impact. A model, encompassing all three topologies, was developed and validated by comparison to experimental results. We found that vertical springless VEHs demonstrate low frequency harvesting (<20 Hz), widebeand harvesting (bandwidths up to BW = 11.2 Hz), and an optimal output power of P = 7.52 mW at a base acceleration of 0.6 g. While horizontal springless VEHs typically offer more output power, the single-impact regime of the vertical springless VEHs offers the simultaneous advantages of wider harvesting bandwidths at lower operating frequencies.

This work reports the design and opto-mechanical characterization of high velocity comb-drive actuators producing in-plane motion and fabricated using the technology of deep reactive ion etching (DRIE) of silicon-on-insulator (SOI) substrate. The actuators drive vertical mirrors acting on optical beams propagating in-plane with respect to the substrate. The actuator-mirror device is a fabrication on an SOI wafer with 80 μm etching depth, surface roughness of about 15 nm peak to valley and etching verticality that is better than 0.1 degree. The travel range of the actuators is extracted using an optical method based on optical cavity response and accounting for the diffraction effect. One design achieves a travel range of approximately 9.1 µm at a resonance frequency of approximately 26.1 kHz, while the second design achieves about 2 µm at 93.5 kHz. The two specific designs reported achieve peak velocities of about 1.48 and 1.18 m/s, respectively, which is the highest product of the travel range and frequency for an in-plane microelectromechanical system (MEMS) motion under atmospheric pressure, to the best of the authors’ knowledge. The first design possesses high spring linearity over its travel range with about 350 ppm change in the resonance frequency, while the second design achieves higher resonance frequency on the expense of linearity. The theoretical predications and the experimental results show good agreement.

This work reports the design, implementation and testing of a parallel plate actuator providing an in-plane motion and achieving a travel range that is larger than 1.5 µm at a resonance frequency of 89.9 kHz, which indicate the high velocity the actuator can accommodate while being in resonance under atmospheric pressure. The modes of the micro-mechanical structure where analysed using the finite element ANSYS tool and the effect of the flexure structure non-linearity where taken into account program and minimized by the optimized design. A structure comprising the MEMS actuator and a micromirror is fabricated using the Deep Reactive Ion Etching (DRIE) technology on Silicon-On-Insulator (SOI) wafer. The structure is characterized optically by counting the interferometric fringes formed in-between the micromirror surface and a standard single-mode fiber at the wavelength of 1550 nm.

Notch filters are used in spectroscopy, multi-photon microscopy, fluorescence instrumentation, optical sensors and other life science applications. One type of notch filter is based on a fibercoupled Fabry-Perot cavity, which is formed by a reflector (external mirror) facing a dielectriccoated end of an optical fiber. Tailoring this kind of optical filter for different applications is possible because the external mirror has fewer mechanical and optical constraints. In this paper we present optical modeling and implementation of a fiber-coupled Fabry-Perot filter based on dielectric-coated optical fiber inserted into a micromachined fiber groove facing a metallized micromirror, which is driven by a high-speed MEMS actuator. The optical MEMS chip is fabricated using deep reactive ion etching (DRIE) technology on a silicon on insulator wafer, where the optical axis is parallel to the substrate (in-plane) and the optical/mechanical components are self-aligned by the photolithographic process. The DRIE etching depth is 150 mu m, chosen to increase the micromirror optical throughput and improving the out-of-plane stiffness of the MEMS actuator. The MEMS actuator type is closing-gap, while its quality factor is almost doubled by slotting the fixed plate. A low-finesse Fabry-Perot interferometer is formed by the metallized surface of the micromirror and a cleaved end of a standard single-mode fiber, for characterization of the MEMS actuator stroke and resonance frequency. The actuator achieves a travel distance of 800 nm at a resonance frequency of 89.9 kHz. The notch filter characteristics were measured using an optical spectrum analyzer, and the filter exhibits a free spectral range up to 100 nm and a notch rejection ratio up to 20 dB around a wavelength of 1300 nm. The presented device provides batch processing and low-cost production of the filter.

Fiber lasers are gaining wide attention nowadays due to their high stability, high reliability, low cost and compactness. Frequency modulation of the laser system has many applications such as wavelength tuning, active mode locking, generation of optical frequency combs and fiber sensors in general. In this work, we report frequency modulation of fiber ring laser system using transmission-type corner cube in-plane MEMS phase modulator fabricated by DRIE technology on an SOI substrate. The fiber-coupled MEMS-based phase modulator is inserted in a multilongitudinal mode fiber ring laser, which has a free spectral range of 345 kHz. By varying the applied voltage on the MEMS device, a wide range of the frequency modulation index can be achieved.

Vibration energy harvesting is the focus of extensive research as an alternative power source for low-power electronic devices. First generation of vibration energy harvesters were based on linear oscillators designed to harvest vibrations in a narrow band in the vicinity of their natural frequency. However, in environments where vibrations are random or distributed over a wide spectrum, those harvesters prove ineffective. In this chapter, we present a new architecter for nonlinear vibration energy harvesters, namely the ‘Springless ’ vibration energy harvesting, that can effectively harvest vibrations over a wide bandwidth and at low levels of vibration. It employs impact oscillators as the harvesting element. We study, characterize, and qualify the performance of those harvesters experimentally, analytically, and numerically.

Notch filters based on fiber-coupled Fabry-Pérot cavity are formed by a reflector placed in close proximity to a dielectric-coated end of an optical fiber. This kind of optical filters is easy to tailor for a given application because the external mirror has less mechanical and optical constraints. In this paper we present a fiber-coupled Fabry-Pérot filter based on dielectric-coated optical fiber inserted into a fiber groove facing a metallized micromirror, where the latter is driven by a high-speed MEMS actuator. The microsystem is fabricated using Deep Reactive Ion Etching (DRIE) technology on SOI wafer. The optical axis is in-plane and the components are self-aligned. The DRIE etching depth is 150 μm; chosen for improving the out-of-plane stiffness of the actuator and increasing the micromirror optical throughput. The MEMS actuator type is closing-gap while its quality factor is improved by slotting the fixed plate. The actuator, therefore, achieves a travel distance larger than 800 nm and has a resonance frequency of 90 kHz. The notch filter exhibits a free spectral range up to 100 nm and a notch rejection ratio of 20 dB around a wavelength of 1300 nm. The presented device provides low cost wafer level production of the filter.

In this work we report an in-line, transmission-type corner-cube optical Phase Modulator (PM) fabricated by DRIE technology on an SOI substrate. The PM has a resonance frequency of 11.2 kHz and a maximum travel range of 5.5 μm. The structure is tested using single-mode fibers in a Mach-Zehnder interferometer configuration at the wavelength of 1550 nm demonstrating the capability of producing both low and high modulation indices by varying the applied voltage.

This work reports the design, implementation and testing of an in-plane comb-drive actuator achieving a travel range of 17.8 μm at a resonance frequency of 26 kHz, and monolithically integrated with a vertical micromirror. The product of the travel range and the frequency is 463 μm.kHz, indicating the maximum linear velocity of the micromirror, is the highest of a MEMS in-plane actuator reported under atmospheric pressure, to the best of the authors' knowledge. The design is fabricated using the DRIE technology on an SOI wafer and tested optically by counting the interferometric fringes formed between the micromirror surface and a standard single-mode fiber at the wavelength of 1550 nm.

We investigate a new type of nonlinear vibration energy harvester that uses a double impact oscillator as its harvesting element. A prototype of the harvester is analyzed numerically and experimentally when aligned vertically. Results show that the new architecture enhanced the output power as well as the frequency bandwidth in comparison with linear harvesters. The new harvester is capable of generating up to 250 mV and has a harvesting bandwidth of about 6 Hz. The optimal load for 0.7 g input acceleration is found to be 5.5 Ω and the corresponding optimal power is determined to be 8 mWatts.

This paper presents a performance comparison of three commonly-used MEMS springs: Double-folded, U-shaped and fish-hook, which are attached each to a same-size proof-mass constituting a mass-spring resonating system oscillating in-plane at 10 kHz. ANSYS Finite Element Analysis (FEA) is performed in order to compare the modal and static analysis among the springs. The effect of fabrication imperfection is also included in the comparison. It is found out that the analyzed Double Folded Beam (DFB) spring demonstrated strongest immunity of about 1% frequency deviation to MEMS fabrication imperfections and against off-axis errors.