In 2004 ITT Exelis developed the Multifunctional Fiber Laser Lidar (MFLL) for measuring atmospheric CO<sub>2</sub>. This lidar relies on high efficiency telecom laser components and Erbium Doped Fiber Amplifiers (EDFA’s) to implement a unique Continuous Wave (CW) Intensity Modulated (IM) differential absorption lidar measurement. This same
approach has also been used to measure atmospheric O<sub>2</sub> by replacing the EDFA’s with fiber Raman amplifier technology. The use of all fiber coupled components results in a highly reliable, flexible and robust instrument. The general architecture of the MFLL, its implementation for greenhouse gas measurements, and as a pseudorandom noise encoded altimeter system is reviewed. Results from a 2011 flight campaign on the NASA DC-8 aircraft which included CO<sub>2</sub>, O<sub>2</sub>, and PN altimetry using a single receiver for all three measurements are also discussed. In addition, an introduction to a novel variation of this approach that will enable greenhouse gas monitoring from a geostationary orbit is given. This paper provides a general overview of a set of applications for fiber lasers in the area of active remote sensing that have been developed by Exelis over the past several years.