The technology requires binoculars because the transmission and reception technology are completely separate and are mounted on separate lenses. The transmitter combines 9-14 light emitting diodes (LEDs) in the infrared range depending on the specific configuration. The energy generated by the LEDs is pulsed into a prism containing a beam splitter designed by Torrey Pines Logic that directs the light out through the lens system on that side of the binoculars. The system requires between 0.25 and 1 watt of power to transmit depending on the type of data being sent. Batteries can power the system for up to six hours, allowing for mobile use, or the device can be plugged into a fixed power source for continuous use. Specifics of how the receiver side works have not been released at this time.
Developed under a grant from the Navy that required usable technology within 12 months, LightSpeed was developed primarily from existing parts that were modified and reconfigured for this purpose. The inspiration for the LightSpeed binocular solution was the Navy’s BigEyes system mounted on ships and used to detect buoys and other ships. The BigEyes system is the same size as standard issue Marine binoculars so the first prototypes were designed to work with both types of oculars. These prototypes successfully transmitted voice, video, and data at one megabit per second across a distance of two nautical miles, but the system should work at a distance up to 12 miles.
There are drawbacks of using optical communications. The largest is that a line of sight must be maintained between the sender and the receiver. However, because the system uses LEDs, the signal spans the entire angular range of the optical system, usually seven degrees for binoculars. Thus, as long as the two seven degree cones overlap even slightly communication is possible. This is a significant advantage over laser communications which use a very tight beam and require much more direct line of sight connections. The system can also degrade in heavy fog or other poor weather conditions that affect visibility; the extent of this has not yet been quantitatively measured.
TFOT has previously reported on other innovative optics systems including optical textiles capable of monitoring MRI patients during their scans, nanoscale particles that can self assemble into different types of optical devices, a series of five large lenses arranged into a camera designed to detect dark matter, and DARPA scopes that use atmospheric turbulence effects to enhance images.
Icon image credit: Lars Plougmann (London, United Kingdom)