Title :
Two-Axis MEMS Lens Alignment System for Free-Space Optical Interconnect
Author :
Yoxall, Brian E. ; Walmsley, Robert ; Kuo, Huei-Pei ; Wang, Shih-Yuan ; Tan, Mike ; Horsley, David A.
Author_Institution :
Dept. of Mech. & Aerosp. Eng., Univ. of California, Davis, CA, USA
Abstract :
We present a two-axis microelectromechanical systems (MEMS) lens aligner with a 260 μm × 220 μm translation range that positions a 6.35 mm lens with focal length f = 12.1 mm for alignment compensation of free-space optical interconnects (FSOIs) between computer servers separated by 50 mm spacing. Efficient ultrasonic linear piezoelectric motors (PMs) provide actuation with zero power required to hold the lens alignment. A four-channel FSOI is demonstrated with 1 × 4 vertical cavity surface-emitting laser (VCSEL) and photodiode (PD) arrays capable of 10 Gb/s transmission bandwidth. Demonstrated minimum step size of 1.68 μm is sufficient for aligning the 20 μm VCSEL spots onto the 40 μ m PD receivers. Force transmission between PMs and a silicon MEMS flexure stage is accomplished using a 1-mm steel ball bearing in a magnetic groove, providing compliance in the nondriven axis. The ball-coupling design has 15 μm backlash and induces a maximum of 8 μm of cross-axis motion.
Keywords :
ball bearings; elemental semiconductors; lenses; linear motors; micro-optomechanical devices; optical design techniques; optical interconnections; optical receivers; photodiodes; silicon; surface emitting lasers; ultrasonic motors; Si; VCSEL; alignment compensation; ball-coupling design; bit rate 10 Gbit/s; computer servers; cross-axis motion; focal length; force transmission; free-space optical interconnect; magnetic groove; photodiode arrays; silicon MEMS flexure stage; size 1 mm; size 6.35 nm; steel ball bearing; transmission bandwidth; two-axis MEMS lens alignment; two-axis microelectromechanical systems; ultrasonic linear piezoelectric motors; vertical cavity surface-emitting laser; wavelength 20 mum; Force; Laser beams; Lenses; Micromechanical devices; Stators; Vertical cavity surface emitting lasers; Vibrations; Alignment stage; microelectromechanical systems (MEMS); optical interconnect; piezoelectric ultrasonic stepper motor; two-axis actuator;
Journal_Title :
Selected Topics in Quantum Electronics, IEEE Journal of
DOI :
10.1109/JSTQE.2010.2089043
