Description: In this proposal, we propose to demonstrate and build a widely tunable, narrow linewidth, single frequency fiber laser by developing an innovative Er/Yb-co-doped single mode fiber. Such a fiber laser is needed for coherent lidar and interferometric fiber sensing. In Phase I, we will design and fabricate this new fiber, demonstrate fixed wavelength narrow linewidth single frequency fiber laser with linewidth of less than 3KHz, demonstrate wavelength tuning range of greater than 5nm, and demonstrate 5GHz frequency modulation with no any mode-hoping in less than 1ms. Successful demonstration of such a fiber laser will enable many new commercial and military applications.

Benefits: There are a number of potential non-NASA commercial applications for tunable single frequency fiber laser. This eye-safe laser source can be used to build commercial lidar for ranging and surface topography applications, be used as the light source for fiber optical sensing, fast scanning biomedical imaging, and scientific research.

NASA's Science Mission Directorate (SMD) encompasses research in the areas of Astrophysics, Earth Science, Heliophysics, and Planetary Science. A major objective of SMD instrument development programs is to implement science measurement capabilities with smaller or more affordable spacecraft so development programs can meet multiple mission needs and therefore make the best use of limited resources. This proposed tunable narrow linewidth single frequency fiber laser can be used as innovative lidar component for measurements of the atmosphere and surface topography of the Earth, Mars, the Moon, and other planetary bodies. Because it is fiber based, this single frequency laser is compact, efficient, and extremely reliable.