Design and fabrication of an epoxy flow stopper with convex corner compensation of V-grooves on a silicon optical bench for the passive alignment of optical fibers

In this paper, a stopper mechanism is introduced to control the length of the epoxy flow in the V-grooves. In fact, such a stopper is another V-groove which is perpendicular to the V-grooves for passive fiber alignment. During the fabrication of prototypes, one critical issue was identified. Due to the undercutting of wet etching, the right angles at the intersection of the stopper and alignment V-grooves were severely eroded by the etching solution. Consequently the intended ldquocrossrdquo intersection became a diamond shaped area. As a result, the length of epoxy flow could not be precisely controlled. During the course of the present study, a convex corner compensation scheme was implemented to resolve the undercutting problem. A parametric study was performed with various kinds of redundant silicon beam patterns at the corners of the intersection. Experimental results showed that relatively sharp corners could be achieved with certain compensation patterns. Furthermore, the epoxy flow did indeed stop when the flow hit the intersection of the stopper and the V-grooves. The design and processing parameters for the epoxy flow stopper and the convex corner compensation scheme will be discussed in detail in this paper.