Optical MEMS Communication Link
MOICS communication: This test bed demonstrates bidirectional
half-duplex communication from an interrogating transceiver
(laser and photoreceptor) to a MOICS CCR unit and back.
The Tanner MEMS-Based Optical Identification and Communication
System (MOICS) provides secure bidirectional half-duplex communication
between an interrogator unit and a remote unit that includes
a corner-cube reflector (CCR).
First, the interrogator transmits a modulated laser beam
that encodes information (e.g., "Who goes there?").
The remote unit demodulates and decodes the signal.
Communication from interrogator to remote unit
Next, the interrogator transmits a modulated carrier beam
(a raw uplink "supply" beam) that impinges on the
remote unit CCR. The remote unit controller toggles the base
mirror of the CCR, thereby adding further modulation ()
and the remote unit data ()
to the beam reflected back to the interrogator. The interrogator
extracts and decodes the data by isolating signals with the
carrier modulation ()
from other light sources such as the sun, and isolating signals
with the CCR modulation (),
to filter out reflections of the laser off of objects other
than the CCR.
Communication from remote unit to interrogator
Check out our interactive communication
demo! (Requires Java-enabled browser; size is 450 KB.)
This research has been sponsored by the Defense
Advanced Research Projects Agency (DARPA).