Vincent Adrianus Henneken

Statically Balanced Compliant Micro Mechanisms (SB-MEMS): Concepts and Simulation

Compliant mechanisms play an important role in micro mechanical structures for MEMS applications. However, the positive stiffness of these mechanisms remains a significant drawback. This stiffness can be compensated by including a static balancing mechanism (SBM), resulting in a statically balanced compliant micro mechanism (SB-CMM). This paper presents concepts and simulation results of such mechanisms, which could be applied to MEMS (SB-MEMS). Two categories of SB-CMMs are presented for different situations: the balancing force and travel path are either (1) perpendicular to each other, or (2) parallel to each other. The presented concepts provide compliant mechanisms with a finite zero stiffness range at the start or at a further predefined position of the overall mechanism travel range, respectively. The simulation results confirm the validity and performance of the presented concepts, which have been optimized for further evaluation. Incorporation of these concepts can ultimately result in a reliable, smaller, and energy efficient microsystem, having a larger useful travel range.Copyright

In-package MEMS-based thermal actuators for micro-assembly

The paper describes the first fabrication and experimental results in the on-going development of MEMS-based electrothermal actuation devices for lateral XY positioning of an optical fibre to a laser diode chip to improve their coupling efficiency and reduce the overall packaging cost. The deflection performance of bulk silicon U- and V-beam thermal actuators with and without fibre loading has been experimentally determined. This is a part of an investigation of the feasibility of an alternative method of performing micro-assembly tasks, i.e. by means of product-internal assembly functions.

An improved in-plane thermal folded V-beam actuator for optical fibre alignment

This paper presents an improved thermal actuator design, providing high work per unit of chip area. The actuator was developed for high accuracy fibre alignment. This application requires that the fibre tip is moved by pushing close to its end, posing geometric design constraints on the actuator design. The basic structure of the actuator is a parallelogram, consisting of a non-moving base, a bar parallel to the base placed orthogonal to the fibre axis in contact with the fibre, and heater arms and reinforced restraining arms which connect the base and the bar. The heater arms thermally expand when passing a current through them. On either side of the heater arms there is one restraining arm, placed at a slightly different angle with the base and bar than the heater arms. The restraining arms do not heat up, and constrain the motion due to thermal expansion of the heater arms, resulting in a motion of the bar in its longitudinal direction. The performance of this actuator is compared to two well-known alternative thermal actuator configurations. Comparison shows that the improved actuator delivers 15% more work per area, and is therefore considered an attractive alternative solution for purposes such as in-plane optical fibre alignment.

Two-Dimensional Fiber Positioning and Clamping Device for Product-Internal Microassembly

In this paper, we present a microelectromechanical systems-based two-degrees-of-freedom positioning device combined with a clamping structure for positioning and constraining an optical fiber. The fiber position can be controlled in the two directions perpendicular to the fiber axis using two specifically designed wedges that can be accurately moved in-plane. These wedges are positioned using in-plane thermal actuators. Actuation of a fiber tip greater than 25 mum in-plane and 40 mum out-of-plane is achieved with a displacement resolution better than 0.1 m. After aligning the fiber the final position can be maintained by switching off the mechanical clamp, which also uses thermal actuators. The position of the fiber can be kept within 0.1 mum after switching off the mechanical clamp and the positioning actuator. Fiber-to-fiber alignment experiments have been performed and the technique can be extended to fiber-to-laser alignment.

Tolerance Budgeting in a Novel Coarse-Fine Strategy for Micro-Assembly

This paper presents the tolerance budgeting for the coarse assembly step in a novel coarse-fine strategy for micro-assembly. The final assembly step is to be performed using MEMS-based functionality that remains part of the product. Total tolerance build-up due to the coarse assembly and dimensional inaccuracies has been determined for the alignment of a single mode optical fibre to a laser diode, a challenging problem in optical telecommunication.

Exploring the benefits of MEMS for micro assembly tasks

An alternative way of performing micro‐assembly tasks is by means of product‐internal assembly functions. After a coarse alignment step, the parts are fine positioned relative to each other by functionality that is integrated with the product. This functionality includes part actuation, position sensing and part freezing. They replace expensive machinery and delicate manual labour, and are aimed to result in lower total production costs. Micro electro mechanical system (MEMS) technology has important benefits to be used as supporting technology, because it allows for cost reduction (batch production), and structures can be made with small dimensions and high accuracy. The objective of this paper is to develop a reliable and reproducible interconnection technology using MEMS‐based product‐internal assembly functions, by which packaging cost is reduced and yield is improved. The considered case is the packaging of optical fibre to chip couplings.

Micro-fabrication as enabler for sub-μm photonic alignment

In the manufacturing of photonic packages, the alignment of the components must often meet strict precision demands. For several applications, sub-micrometre alignment must be achieved, and this precision needs to be maintained once the components are aligned. In our research we explore the use of micro-fabrication technology as the enabler for reaching sub-μm alignment precision. Two main concepts are presented: the use of micro-actuators for active alignment and the use of mating structures for passive alignment. Results from MEMS-based active fibre alignment and multi-port passive chip-to-chip alignment are described. Finally, the paper discusses the limits and applicability of the two concepts.