A micromachined dual-axis actuator for use in a miniaturized optical communication system
- Paper number
IAC-08.B4.6.B12
- Author
Mr. Kristoffer Palmer, Uppsala University - Ångström Space Technology Centre, Sweden
- Coauthor
Dr. Henrik Kratz, Uppsala University - Ångström Space Technology Centre, Sweden
- Coauthor
Dr. Greger Thornell, Uppsala University - Ångström Space Technology Centre, Sweden
- Coauthor
Ms. Sara Lotfi
- Year
2008
- Abstract
An interesting concept for space exploration is to use multiple satellites in cluster constellations. These offer the advantages of, e.g., increased apertures in interferometry missions, multiple point measurements, and the distribution of tasks among satellites in high-risk missions. By reducing the size and mass of the satellites, the total mass of a satellite cluster can potentially be made equal to, or even smaller than, a single conventional satellite, and at the same time increase both redundancy, and scientific and commercial gain. For effective miniaturization, micromachining is necessary, and today microelectromechanical systems (MEMS) technology begins to play a significant role in space applications.
Effective satellite collaboration requires tremendous communications capacity to fully benefit from high performance instruments generating huge data volumes. However, microwave (RF) communication is not well suited for high-rate links (above some 100s of Mbps), and data rate space links with RF will involve large, high-power transmitter antennas. Free space optics (FSO) communications, based on transmitting near diffraction-limited laser beams, on the other hand, is an emerging technology that has a great potential to satisfy the requirements for high rate data transfer (>10 Gbps). High-performance FSO systems are rather complex assemblies of electric, mechanical and optical devices, not easily integrated in a small volume. In addition, to enable pointing at multiple satellites in a dynamic constellation, the use of individual beam steering devices for each laser is necessary.
In this paper we present a dual-axis bending actuator based on thermally actuated joints consisting of sets of tapered silicon trenches (v-grooves) filled with SU-8 polymer. With our design and fabrication technique, standard silicon batch processing is used to manufacture low-cost miniature beam steering devices weighing less than one gram. In order to steer the beam, the joints are heated causing an expansion of the polymer, and, in turn, a bending of the silicon structure tilting a laser-reflecting mirror. Although polymer-filled v-groove actuators have been presented before, we show here a dual-axis structure with joints exhibiting a small static, but large dynamic bending which is needed in a beam-steering device.
The intention with this work is to show that a relatively straightforward designed and built MEMS actuator can be used as a beam steering device in a miniaturized, integrated optical communication system. Preliminary results show a well behaved deflection covering the desired range of ±15º along two orthogonal axes.
- Abstract document
- Manuscript document
IAC-08.B4.6.B12.pdf (🔒 authorized access only).
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