High Power, High Efficiency Optical Power Amplifiers

Free space optical communications is rapidly becoming the technology of choice for intersatellite links (ISLs). Typical systems utilize high speed laser sources coupled with high power optical amplifiers. We propose the development of a high efficiency,high average power (22W), low noise, optical fiber amplifier for free-space satellite communications. The amplifier supports variable output pulse energies ranging from 2.2nanoJ at 10GHz up to 120microJ at 180kHz repetition rate when seeded with 10 pJ/bit.The amplifier has a 25 GHz bandwidth that can be tuned to match the transmitter/receiver, allowing large signal-to-noise improvement. The predicted signal to noise at the amplifier output is 48 dB in a 25 GHz bandwidth. We will further optimize our designthrough (1) match of gain media and pump lasers, (2) study of various pump geometries. The communications satellite market is rapidly expanding. For communication between satellites the new method of choice is optical data links, as they are morecompact, lighter, and more energy efficient than RF based links. The increased power of our amplifier will enable high transmission rates, up to 100 Gbs. Its variable pulse energy feature will significantly facilitate initial emitter-receiver alignmentand enable operation in high back-ground noise environments.