Berkeley Sensor & Actuator Center Smart dust Active Laser Transmitter (SALT) Matthew Last, Kris Pister Berkeley Sensor and Actuator Center http://www.eecs.berkeley.edu/ ~mattlast
Berkeley Sensor & Actuator Center Smart dust Active Laser Transmitter (SALT) Matthew Last, Kris Pister Berkeley Sensor and Actuator Center mattlast.
Dec 18, 2015
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Berkeley Sensor & Actuator Center
Smart dust Active Laser Transmitter (SALT)
Matthew Last, Kris PisterBerkeley Sensor and Actuator Center
http://www.eecs.berkeley.edu/~mattlast
Berkeley Sensor & Actuator Center
• Free-space Communication • Low-frequency Beam Steering (DC -> 1kHz)
Smart dust Active Laser Transmitter (SALT)
Berkeley Sensor & Actuator Center
Free-Space Communication using Agile Beamsteering• What do we gain over RF?
– High Antenna Gain• Excellent performance: low power, long range, high bit rate• 1mrad, 1mW beam = 318 kW/steradian• Isotropic 1mW radiator = 80 W/steradian Antenna gain of 152 dB for typical laser
– No spectrum regulation issues– SDMA (Space-Division, Multiple Access) with imaging
receivers– Only simple baseband modulation necessary (OOK)
Berkeley Sensor & Actuator Center
Free-Space Communication using Agile Beamsteering (2)• When to use?
– Need Line of Sight– Need Clear Weather (no fog)
• At what cost?– Tight alignment tolerances– Only point-to-point networks (no broadcasting)– Unidirectional links yield asymmetrical networks
Berkeley Sensor & Actuator Center
Long Range, Low Power Crosslinks
(a) 5.2 km Berkeley Marina
(b) 15.3 km Coit Tower
(c) 21.4 km Twin Peaks
3 mW optical power:
And plenty of power to go further…
Berkeley Sensor & Actuator Center
Current Work
Berkeley Sensor & Actuator Center
Performance:
Mechanical Angle of
Deflection
Unactuated
(Probe Tip)
Actuated
(Thermal)
In-plane 45 degrees 11 degrees
Out-of-plane Untested 28 degrees
Berkeley Sensor & Actuator Center
Actuation Power - 1st Generation
Power vs Mechanical Deflection Angle
0
50
100
150
200
250
300
350
0 10 20 30 40
degrees
actu
ato
r p
ow
er (
mW
)
1st DOF
2nd DOF
Berkeley Sensor & Actuator Center
Actuation Power – 2nd Generation
Power vs Mechanical Deflection Angle: 1st DOF, torsion mirror
0
50
100
150
200
250
0 2 4 6
degrees
mW 1st DOF
Berkeley Sensor & Actuator Center
2nd Generation Mirror Pictures:
Berkeley Sensor & Actuator Center
Ongoing Projects:
• Lenses and lens systems– vary lens diameter– lens quality evaluation?
• Laser diode mount• Prototype laser transmitter system (laser diode ->
collimating lens -> 2-DOF mirror)
Berkeley Sensor & Actuator Center
More Pictures:
Berkeley Sensor & Actuator Center
Fun Numbers:
• divergence = 1.22 /d– 1mm aperture @ 650nm .79 mrad divergence– 1mrad divergence @ 650nm .79mm aperture
• 1mW 1mrad emitter puts out 40 times more power/steradian than a 100 W bulb
Related Documents
