Title of Presentation: A Multi Functional Fiber Laser Lidar for Earth Science & Exploration

Primary (Corresponding) Author: Doug McGregor

Organization of Primary Author: ITT Space Systems Division

Co-Authors: Michael Dobbs, William Krabill, Mike Cisewski, F. Wallace Harrison, C. K. Shum, Doug McGregor, Mark Neal, Sheldon Stokes

Abstract: A multi-pixel laser altimeter using pseudo-random-noise-modulated fiber lasers has been developed for Climate Change research and Exploration.The architecture supports a wide set of operational parameters (range resolution, range ambiguity interval, temporal update rate) without modifications to the hardware. These parameters can be changed dynamically, based on mission operational needs. The implementation is suitable for orbital and sub-orbital platforms and has reached TRL 6 having flown in a relevant environment over relevant terrain.

The transmitter is presently implemented using a fiber amplifier at 1um, but can be just as easily implemented at optimal wavelengths for vegetation, ice sheet topography, bathymetry, aerosols, clouds, lunar and planetary surfaces. Robust fiber optical transmitters are available today at wavelengths ranging from 1um to just over 2um, and development of new capabilities continues at a rapid pace. Shorter wavelengths are reached by modulating an existing laser diodes or by using second harmonic generation techniques. Longer wavelengths can be reached using Interband-Cascade and Quantum-Cascade laser diodes.

The present receiver uses silicon-based single-photon-counting detectors which are available with very large pixels, no dead time, and are packaged as individual detectors, linear and 2D arrays. The present imaging format is a pushbroom agumented with fore and aft pixels for improved geolocation. The imaging format is physically implemented using an array of optical fibers which are coupled to discrete detector modules; however with the recent release of large pixel linear and area arrays, a direct imaging system is easily implemented.

We will present the status of the instrument development efforts, the results from the on-going field campaign, and notional implementations for Earth Science Decadal Missions and Exploration.