Development of a large area InGaAs APD receiver based on an impact ionization engineered detector for free-space lasercomm applications

The U.S. Naval Research Laboratory (NRL) is developing a small size, weight and power (SWaP) free space lasercomm terminal for small unmanned airborne platforms. The terminal is based on a small gimbal developed by CloudCap Technology. A receiver with a large field of view and with sensitivity sufficient to meet the program range goals is required for this terminal. An InGaAs Avalanche Photodiode (APD) with internal structures engineered to reduce excess noise and k eff in high gain applications was selected as the detector. The detector is a 350 micron diameter impact ionization engineered (I 2 E) APD developed by Optogration, Inc. Results of development and characterization of the receiver will be presented.