An array of free-space optical interconnects composed of vertical cavity surface emitting lasers (VCSELs), alignment lenses, and photodiodes can alleviate communication limitation between boards in computer servers by replacing traditional copper wire connections. Actively controlled alignment lenses can be used to correct optical misalignment due to vibration loads, temperature fluctuation, and initial static offsets. A silicon micro-machined lens stage has been designed and fabricated to interface between linear piezoelectric ultrasonic stepper motors (USM) and an alignment lens for the VCSEL array. The linear stepper motors offer an advantage of zero power requirement once the lens is aligned, with position maintained by friction in the motor slider. The USMs have been characterized to provide 1 micron position resolution with a 3 millimeter travel range. Integration of the flexure, lens, and micromotors is complete with demonstrated 2 axis beam alignment correction. The loaded performance of the system has been characterized in a closed-loop controlled test setup.
Project end date: 08/09/10