Beam steering system using a 2D MEMS scanner

Fiber optical modules manufacturing have been recognized as a key challenge in meeting the anticipated demand for high bandwidth telecommunication equipment. Among all challenges, submicron optical alignment for single mode fiber remains the predominant difficulty [1]. To reduce the alignment effort during the assembly, a XY micro stage has been developed. It consists of a scanning platform with a mounted micro-lens on top (Figure 1). After a passive alignment of the components and the sealing of the package, a fine tuning of the lens position and thus the optical coupling efficiency can be made by actuating the MEMS chip. By placing a lens on the 2D movable platform of a MEMS scanner, it is possible to steer the light beam coming out of the laser diode and couple it into a single mode fiber. The 2D displacement of the lens is provided by 2 linear combdrive pairs and curved beams transform the initial linear motion of the combdrives actuators into a 2D displacement. This system is developed to actively align optical components to optimize the coupling of light coming from a laser diode into an optical fiber [2]. The scanner allows a post assembly fine lateral positioning of the lens focusing the light into the fiber. As the lens motion is limited to two dimensions, the device has to be precisely aligned in the direction parallel to the light beam. For this reason, a new assembly concept based on a stacked assembly of silicon devices was developed (Figure 2). A first silicon substrate containing the electrical routing supports the electronic components, the laser diode and a turning mirror. The MEMS device with its movable lens is then assembled on top of it and a cover glass seals the whole system. The connections are made through a flex flip-chip bonded to the device