Description: In this proposal, we propose to demonstrate and build high pulse energy near 1.55 micron wavelength single frequency fiber laser by developing an innovative polarization maintaining Er-doped gain fiber with extremely large mode field diameter. Such a single frequency high energy and high peak power fiber laser is needed for coherent lidar and sensing. We will enhance the radiation resistance of the gain fiber in order to make it suitable for NASA's applications. In Phase I, we will design and fabricate Er-doped glasses, fiber preforms, and fibers. High pulse energy will be demonstrated. This proposed system will be all-fiber based, which offers excellent reliability. Successful demonstration of such a fiber laser can enable many new NASA and commercial applications.

Benefits: This proposed 1.55 micron single frequency high energy and high peak power fiber amplifier can be used as innovative lidar component for measurements of the atmosphere and gas content of the Earth, Mars, the Moon, and other planetary bodies. Because it is all-fiber based, this single frequency amplifier is compact, efficient, and extremely reliable. The proposed gain fiber exhibits excellent radiation resistance, which is suitable for NASA's space applications.

This 1.55 micron single frequency high energy and high peak power fiber laser have a number of potential non-NASA commercial applications. This eye-safe laser source can be used to build wind lidar for ranging and gas monitoring applications, be used as the light source for optical sensing, fast scanning biomedical imaging, and scientific research.