Tae-Sun Lim

Electrostatic MEMS variable optical attenuator with rotating folded micromirror

The design and fabrication of an electrostatic MEMS variable optical attenuator (VOA) is described. The VOA is a reflection type with a folded micromirror actuated by a comb-drive actuator. The VOA is fabricated by a simple single-mask process. One photolithography and subsequent deep silicon reactive ion etching define all the microstructures of the VOA. The folded micromirror structure can reduce the overall size of the device by enabling the parallel alignment of an input fiber and an output fiber. Lensed fibers are used to maximize the coupling efficiency and the ease of assembly. The electrooptic characteristics and dynamic characteristics of fabricated VOA are measured. The initial insertion loss is 0.5 dB at 1550 nm and the maximum attenuation is 45 dB, respectively. The polarization dependent loss is measured to be 0.2 dB at 20-dB attenuation. The response time for maximum attenuation is less than 5 ms.

Electrostatic MEMS variable optical attenuator with folded micromirror

A reflection type VOA with folded micromirror was designed and fabricated. The proposed mirror structure can reduce the size of device by parallel alignment of the two fibers. Lensed fibers are used for high coupling efficiency and ease of assembly. The initial insertion loss is about 0.6 dB and the maximum attenuation is about 30 dB. The switching time of the fabricated VOA is about 1 ms.