Chia-Yu Wu

Study of electrothermal V-beam actuators and latched mechanism for optical switch

We present new optical switch devices based on a bi-stable microelectromechanical structure driven by two sets of one-directional movable electrothermal V-beam actuators. In conjunction with the movement translation link structure, or T-shaped end of the switch body, and buckle springs, the first V-beam actuator set can drive the in-plane moving reflective shutter from one rest position to the second stable position, while the second V-beam actuator set is able to drive the reflective shutter back to the original rest position. The transmission state of the optical switch device could be one of these bi-stable positions, and the switching state will be the counter position. Thus, the bi-directional motion capability is realized by using a pair of V-beam actuator sets with opposite directions of motion. We have optimized the design of V-beam actuators according to the application requirements. The preliminary results prove the application feasibility.

3-V driven pop-up micromirror for reflecting light toward out-of-plane direction for VOA applications

Novel axial aligned fiber-to-fiber variable optical attenuator (VOA) that used a pop-up micromirror to reflect the attenuated light toward out-of-plane was designed and characterized. Unlike axial-type VOA devices that suffer from large return loss and large operation voltage, U-shaped electrothermal actuator array only requires 3-V dc bias to achieve 37-dB attenuation in our new design. Insertion loss, return loss, and wavelength-dependent loss at attenuation of 3 dB were measured to be 0.3, -45, and 0.28 dB, respectively.

Development of Electrothermal Actuator with Optimized Motion Characteristics

In this paper, we give the reasons for the phenomenon of adhesion of U-shaped electrothermal actuators onto substrates which is commonly observed for such devices. Next, we identified a significant advantage for operating these U-shaped actuators on top of a polysilicon layer with a suitable pattern design. A thorough investigation on the deflection behavior of actuators with different dimensional parameters, i.e., cold arm width, flexural beam length and hot arm length, was carried out. Finally, we discussed the effects of electrostatic force on the actuator due to these parameters. Based on these analyses, we suggested optimized dimensions for the U-shaped actuator.

Feasibility study of self-assembly mechanism for variable optical attenuator

This paper describes the feasibility study result for a variable optical attenuator (VOA) realized by a new concept of self-assembled polysilicon structures and a continuously position-controllable curved beam actuator based on surface micromachining technology. The self-assembly mechanism includes a residual stress induced curved beam which lifts up the reflective mirror shutter first. This self-assembled reflective pop-up shutter is locked and fixed on a curved polysilicon beam actuator which is connected with a polysilicon frame clamped on the substrate. Secondly, a set of polysilicon scratch drive actuators drives the frame, curved beam actuator and shutter moving forward and sliding into the space between the two ends of the input and output fiber ports. The optical attenuation range of the proposed VOA is determined by the vertical position of the self-assembled reflective shutter which is controlled depending on the applied voltage value. This new VOA has demonstrated continuous attenuation capability and wide attenuation range. This device demonstrates 70 dB attenuation range and less than 1 dB insertion loss.

Scratch Drive Actuator Driven Self-assembled Variable Optical Attenuator

This paper describes the new concept and design for a self-assembled variable optical attenuator (VOA) derived by using surface micromachining technology. A residual stress-induced flexure curved beam with corrugated trench anchors can lift up the reflective mirror shutter. This self-assembled reflective shutter can be driven by a set of scratch drive actuator (SDA), then slides into the spacing between input and output fiber ends. The attenuation range of proposed microelectromechanical systems (MEMS) VOA is determined by the vertical position of self-assembled pop-up polysilicon reflective shutter in which it is controlled by the value of applied dc voltage. This new VOA demonstrates continuous attenuation capability and wide attenuation range based on using an electrostatic actuator that is a new residual stress-induced flexure curved beam with corrugated-trench anchors. This device exhibits attenuation range of 70 dB and insertion loss less than 1 dB.

Bi-directional movable latching structure using electrothermal V-beam actuators for optical switch application

We present a new bistable MEMS structure driven by a pair of electrothermal V-beam actuators with capability of bi-directional motion. The preliminary results enable its application possibility for optical switch.

Characterization of Bi-Stable Micromechanism Based on Buckle Spring and Electrothermal V-Beam Actuators

We present a novel bi-stable microelectromechanical structure driven by a pair of one-directional movable electrothermal V-beam actuators for applications need latch functions, like optical switch and relay. In conjunction with the T-shaped end and buckle spring, the first V-beam actuator set can drive the in-plane moving reflective mirror from transmission state to switching state, while the second V-beam actuator set is able to return the reflective mirror from position of switching state to position of transmission state. Thus the bi-directional motion capability is realized by using a pair of V-beam actuator sets with opposite moving direction. The preliminary results prove its application feasibility.

Bi-directional movable latched micromechanism using one-directional movable Chevron electrothermal actuators for switch and relay applications

In this paper, we present a creative bi-directional movable latched micromechanism for switch and relay application. Bistable microelectromechanical (MEM) mechanisms provide two relative positions that are both mechanically stable. Preliminary results prove this new design is promising in optical switch application.

Development of Surface Micromachined Mechanism for Movement Translation and Displacement Amplification

Characteristics of motion and movement are key concerns for microactuators and microrobots. We propose a new surface micromachioned mechanism to transfer small in-plane motion or displacement into the out-of-plane amplified rotation or amplified vertical projected displacement. We have demonstrated the concept of using this micromechanism to optical switch and variable optical attenuator (VOA) applications. Experimental data confirm its function of transferring and amplifying in-plane motion and movement into out-of-plane motion and movement. Preliminary results prove this mechanism can drastically reduce the driving voltage, thus the reported VOA device only requires 3 volts dc load to achieve 37 dB attenuation range.

Fabrication of corrugated curved beam type electrostatic actuator and SDA driven self-assembling mechanism for VOA applications

In this paper, we present an innovative design of corrugated curved beam type electrostatic actuator with continuous motion capability, and SDA (scratch drive actuator) driven self-assembling mechanism for axial type MEMS VOA application.