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A novel electromagnetic energy harvester structure with a highly efficient closed magnetic circuit is presented. An opposite polarity arrangement of a permanent magnet pair results in the maximum change of magnetic flux linkage in the solenoid when the energy harvester is in vibration. The strong coupling between the stator iron cores and the vibrating permanent magnets leads to significantly enhanced output voltage and power and a broadened operation bandwidth. Compared to open magnetic circuits, a closed magnetic circuit can effectively improve the output voltage and power. A maximum root mean square output voltage of 67 mV, a working bandwidth of 7.3 Hz, and a load power of 3.04 µW are obtained from the prototype at an acceleration of 5 m/s2.

This paper describes a new fabrication technology for high aspect ratio magnetic microstructures. These microstructures are made of composite magnetic materials. In this new technology, a master mold was made using photolithography and the mixture of magnetic particles and polymer was used in micro-molding process. The microstructures were then thermally cured at a temperature lower than 80 °C. To demonstrate the feasibility of using the technology in making magnetic microstructures, both hard magnetic and soft magnetic particles were tried in our experiments. The magnetic particle sizes ranged from 2.3 to 44 μm, which sets the limitations in feature sizes achievable for the magnetic microstructures. Different weight ratios were tried, the maximum weight ratio between the magnetic particle and the polymer was over 2:1. For both wall and trench microstructures, the maximum aspect ratio was found to be over 10, which demonstrates its great potential for micro-fabrication applications.

This paper discusses fabrication and performance of novel circular spiral inductors on silicon. The substrate materials underneath the inductor coil are removed by wet etching process. In the fabrication process, fine polishing of the photoresist is used to simplify the processes and ensure perfect contact between the seed layer and the top of pillars. Dry etching technique is used to remove the seed layer. The results show that Q-factor of the inductor is greatly unproved by removing silicon underneath the inductor coil. The spiral inductor with line width of 50 fan has a peak Q-factor of 10 for the inductance of 2.5 nH at frequency of 1 GHz, and the resonance frequency of the inductor is about 8.5 GHz. For the inductor of conductor width of 80 µm, the peak Q-factor increases to about 17 for inductance of 1.5 nH in the frequency range of 0.05–3.00 GHz.

This paper presents a bistable microswitch fully batch-fabricated on a single glass wafer, comprising of a microactuator, a signal transformer, a microspring and a permanent magnet. The bistable mechanism of the microswitch with large displacement of 160 μm depends on the balance of the magnetic force and elastic force. Both the magnetic force and elastic force were optimized by finite-element simulation to predict the reliable of the device. The prototype was fabricated and characterized. By utilizing thick laminated photoresist sacrificial layer, the large displacement was obtained to ensure the insulation of the microswitch. The testing results show that the microswitch realized the bistable mechanism at a 3–5 V input voltage and closed in 0.96 ms, which verified the simulation.

This paper presents non-silicon MEMS technology for fabrication of Optical communication components. Both pure non-silicon and combined micromachining technologies were realized. For the pure non-silicon surface micromachining technology, the Ni and permalloy were chosen as the structure layer; the photo resist and copper were chosen as the sacrificial layer. Based on the technology, the micro-hinge was realized. It may find ample application in the out-of-plane microstructure, which is common in free-space optical transmission. As an example, a MEMS variable optical attenuator is introduced. It consisted of a hinged shutter to adjust the optical power transmission between the input and output optical fibers. For the combined micromachining fabrication, the electroplating was combined with the traditional bulk silicon technology to realize some unique structure for passive alignment. For example, we had developed the micro-fabricated nickel clamps for packaging of optical fibers in photonics devices. Compared with the all silicon scheme, this approach only involves one additional sputtering, photolithography, and electroplating process.. The presented non-silicon micromachining process offered more choice of material and facilitated the implementation of structure innovation.

Optical power equalization between wavelength-path slots in wavelength division multiplexing (WDM) networks is an increasingly concerning issue in all-optical networks, and this made variable optical attenuators (VOAs) play an increasingly important role in fiber optic transmission systems. Various types of optical attenuators have been realized, but conventional available mechanical VOAs are bulky, costly, and slow. MOEMS technology provides new approaches to improve the characteristic mentioned above. Previous attempts to realize MEMS variable optical attenuators include the use of a micro-driven shutter, a mechanical antireflection switch (MARS) modulator, a micro-machined tilted mirror, and a micro-machined membrane-type waveguide. In this paper, we report the design and fabrication of two types of electromagnetically actuated variable optical attenuator (VOA). They are both driven by a similar construction containing of a plane coil and a FeNi armature. The first one adjusts the attenuation by moving a shutter between the two fibers, the second one by moving one of the fibers directly. The first one is fabricated by nonsilicon surface micromachining technology. In which a copper layer was used as the sacrificial layer, and the electroplated FeNi as the structure layer. This scheme provides another way to fabricate the optical microstructure. According to the experiment results, it has insertion loss less than 3 dB at 1550-nm wavelength, dynamic range greater than 40 dB, 0.2-dB repeatability, and return loss better than 40 dB, driving voltage less than 20 V. For the second one, it included the silicon platform for adjustment of optical coupling between two optical fibers. The main fabrication process of the silicon platform is was the KOH antistrophic wet chemical etching of silicon wafers. The silicon wafer is further selectively etched from the bottom side to subtract the thickness of the silicon elastic platform. In addition, two V grooves were fabricated for alignment of the input and output optical fibers. One of the V grooves is on the mobile elastic platform; the other is on the fixed framework. When the platform is attracted downward by the electromagnetic force, the central axes of the two fibers are mismatched to adjust the attenuation. The insertion loss is less than 1 dB, the polarization dependent loss is less than 0.1 dB, dynamic range is larger than 50 dB, and the driving voltage is less than 5 V. The design, fabrication, and test of the two devices are all introduced detailedly below. The first device is suitable for fast adjustment. The second one may be adopted in applications where, the fabrication cost and polarization-dependent loss is of more concern.

An electromagnetically actuated MEMS variable fiberoptic attenuator was designed and fabricated. The device consists of an electromagnetic microactuator, a fiber alignment component, a ferronickel shutter, and two single mode fibers. The shutter actuated by the microactuator was interposed in the gap between input and output fiber, which can regulate the optical output. Non-silicon surface micromachining technology, which uses copper layer as the sacrificial layer and the electroplated ferronickel as the structure layer, was used to fabricate the shutter. The magnetic and mechanical behaviour of the device was investigated by using analytical methods and ANSYS FEM, and some its geometric structural parameters were then optimized. The attenuator has less than 3dB-insertion loss at 1550nm, greater than 45dB dynamic range, and better than 40dB return loss.

An eight-channel variable optical attenuator (VOA) array fabricated by MEMS technology is presented. Based on micro electromagnetic actuation, the attenuation level is adjusted by changing the radial offset between the input/output optical fiber. The relationship between the attenuation and the offset was analyzed based on wave-guide transmission theory. The structure parameter was determined through mechanics and magnetic circuit analysis. The device was fabricated and packaged by micromachining technology. The packaged volume of the device is 80×40×12mm 3 . According to the experiment results, the insertion loss is less than 1dB, the polarization dependent loss is less than 0.1dB, dynamic range is above 35dB and the driving voltage is less than 5V. It is proved to be a low cost, high performance passive device for future all-optical-networks.

For Dynamic Power Equalization in all optical networks, a magnetically actuated, surface micromachined micro shutter in variable optical attenuator (VOA) has been fabricated and characterized. The fabrication of the micro shutter is based on the nonsilicon surface micromachine technology. The electroplated FeNi are used as the structure layer, the photoresist and Cu is adopted as the sacrificial layer. In addition, the theoretical analysis of the diffraction optical propagation through the micro shutter in the VOA has also been carried out. The analysis is based on a gaussian beam approximation to the fiber mode, a calculation of the free space diffraction past a square aperture based on the Fresnel-Kirkhoff diffraction integral, and the mode-overlap integral between the diffracted beam and the fiber mode. The theoretical calculation result is in good agreement with the experimental data. Based on the model set up, the performance of the VOA can be optimized for better adjustment characteristics.

Power management is an increasingly concerned issue in all-optical network, where the continuous adjustment of the transmitted power is required. In this paper, the diffractive optical propagation inside a magnetic actuated, surface micromachined variable optical attenuator has been modeled and characterized. The modeling of the diffractive optical propagation is based on a gaussian beam approximation to the fiber mode, a calculation of the free space diffraction past a square aperture based on the Fresnel-Kirkhoff diffraction integral, and the mode-overlap integral between the diffracted beam and the fiber mode. The fabrication of the attenuator is based on the nonsilicon surface micromachine technology. The experimental data is in good agreement with the theoretical calculation result. Based on the work, a variable optical attenuator (VOA) has been successfully developed.

Considering the radius difference among layers and nonlinear temperature distribution inside the fiber coil, a simple, accurate model for the quantitative analysis of the thermal induced nonreciprocity in sagnac interferometer has been put forward and confirmed by experimental results. Based on the model, a novel approach to reduce the Shupe effect by 60% has been figured out.

Power management is an increasingly concerned issue in Dense Wavelength Division Multiplexed (DWDM) network. It poses strict comprehensive requirements, such as electronic controllability, cost and volume, etc, on the Variable Optical Attenuator (VOA). The characteristics of MEMS technology make it to be one of the most prospective candidates to meet these requirements. This paper consists of three parts. The first part is a description of VOA application in all-optic network. In the light of these aspects, the main requirements for VOA devices are quantitatively identified. In the second part, the current situation of research on MEMS based VOA is presented extensively. Finally, several novel applications of MEMS based VOA in all optic networks are illustrated. It illustrates the premise that MEMS VOA can bring added capability or new functionality to optical designs and increase the incentive to explore their potential in lightwave subsystems. Considering the attractive market volume in 2008, MEMS based VOA seems to be one of the most prospective candidates for the commercialization of optical MEMS technology.

Reports the microfabricated nickel clamps for packaging of optical fibers in photonics devices. When the fiber is inserted into the silicon V groove, the microfricated clamps fix it in the V groove. Compared with the traditional silicon V grooves, this approach only involves one additional sputtering, photolithography, and electroplating process. Two single-mode optical fibers were fixed into the silicon V groove by the nickel clamp; the measured insertion loss is lower than 0.1 dB.

A novel, electromagnetically driven variable fiber optic attenuator based on micro-electromechanical system (MEMS) technology is described. The attenuation level is adjusted by changing the microshutter position in the optical path. A new technique, termed "nonsilicon surface micromachining," is used to fabricate the shutter, in which a copper layer was used as the sacrificial layer, and the electroplated FeNi as the structure layer. This scheme provides another way to fabricate the optical microstructure. The optical characteristics of the attenuator are theoretically analyzed, and the result is verified by experiments. The MEMS attenuator has fiber-to-fiber insertion loss less than 3 dB at 1550-nm wavelength, dynamic range greater than 40 dB, 0.2-dB repeatability, and return loss better than 40 dB.

A novel micromachined electromagnetic actuated variable optical attenuator is described. The attenuation level is adjusted by changing the lateral distance between two V-groove-aligned single-mode fibers. Based on the waveguide transmission theory, the relationship between the attenuation and the offset is analyzed. The fabrication of the device only enrolls common and well-known semiconductor technologies. The packaged volume of the device is 20×10×5 mm3. According to the experiment results, the insertion loss is less than 1 dB, the polarization dependent loss is less than 0.1 dB, dynamic range is larger than 50 dB, and the driving voltage is less than 5 V. It is proven to be a low-cost, high-performance passive device for future all-optical networks.

A fast switching electromagnetic microactuator with two stable positions is presented. The actuator of size 2.0×2.2 mm is fabricated using UV-LIGA technology. Test results show that a current pulse with an amplitude of 50 mA is needed for the actuator's switching between two stable states, and the switching time is approximately 20 µs. The displacement of the actuator is about 17 µm.

A simple, accurate model for the quantitative analysis of the Shupe effect in a Sagnac interferometer has been put forward and confirmed by experimental results. Based on the model, the thermal phase-drift contribution of each layer has been evaluated and a novel approach to reduce the Shupe effect by 60% has been developed.