Packaging of Optical MEMS Devices

Recently, optical MEMS devices have gained considerable attention in the telecommunications industry—particularly in the optical networking and switching arenas. Since optical MEMS are micro-systems which rely on high precision optics, electronics and mechanics working in close concert, these emerging devices pose some unique packaging challenges yet to be addressed by the general packaging industry. Optical MEMS packages often are required to provide both optical and electrical access, hermeticity, mechanical strength, dimensional stability, and long-term reliability. Hermetic optical access necessitates the use of metallized and anti-reflection coated windows, and ever-increasing electrical I/O count has prompted the use of higher density substrate/package technologies. Taking these requirements into consideration, we explore three ceramic packaging technologies, namely high-temperature co-fired ceramic (HTCC), low-temperature co-fired ceramic (LTCC), and thin-film ceramic technologies. In this paper, we describe some optical MEMS packages designed using these three technologies and discuss their substrate designs, package materials, ease of integration and assembly.