Optical Jitter Control for Laser Communications

DoD is actively pursuing transformational communication technologies that need space, airborne, and ground nodes (transmitter/receiver sets) to acquire and stabilize laser communication links. A small, low-cost, but accurate optical inertial reference unit is an enabling technology for these systems. Optical telecommunications requires precisely pointed and stabilized transmit and receive paths to accommodate the narrow beam of laser light on which data are carried. Systems that perform functions of pointing and acquisition in the presence of linear and angular spacecraft vibrations need to do so with angular jitter that is fraction of a micro-radian and inertial attitude knowledge (IAK) of a few microradians. Applied Technology Associates (ATA) proposes a new optical inertial reference unit (MIRU-LC) and associated control software that increase capability and robustness of laser communication while reducing size, weight and cost. ATA has patented and advanced technology related to optical systems line-of-sight stabilization and pointing based on magnetohydronamic (MHD) inertial rate sensors. New hybrid sensor innovations allow an optical inertial reference unit to perform over broad bandwidths (0 to 2kHz), maintain continuous absolute inertial pointing knowledge at microradian performance levels, and provide an optical reference beam (ORB) with jitter less than 500 nrads. The technology advances occur in the areas of: (1) smaller, lighter inertial sensors based on MEMS/MHD hybrid innovations; (2) electronics and software for blending of signals using information theoretic principles; and (3) algorithms that mitigate against vibrations and momentary loss of cooperative tracking.