Low Power Retroreflectors for Optical Communications

Optical retro-reflectors have been used for communications for many years. The approach has many advantages, when one terminal has limited power, space, weight, and a low cost as requirements. The major limitation for “Retro-Comms” has been that the modulator consumes too much power at higher modulation rates. What we propose is to reduce the power, size, weight and cost of the Retro-Modulator (RM) by improving the design of a deformable mirror, and its drive electronics. The RM device is largely capacitive, and the drive electronics and the modulation approach can be optimized so that the energy is recycled and dissipation is minimized. Further, we propose to use a co-located Photo-Voltaic converter to convert a part of the incident light to power the RM driver, and electronics. A further aspect of our design is that it can be deployed as a projectile. During Phase I we will design the circuitry, and test existing RM devices, capable of 100 kHz modulation, to improve the basis for designing higher performance devices. In Phase II, we will demonstrate the new design, and show modulation of beams at ~1500 kHz, with high beam quality retro-reflections. In Phase III we will do a full system demonstration.