50 mJ Monolithic 2 um Pulsed Fiber Laser Transmitter in 200 ns Regime with Transform-Limited Linewidth Based on Highly Tm-Doped Germanate Fibers

For NASA's various types of coherent LIDAR applications, NP Photonics propose to develop a 50 mJ monolithic 2 micron pulsed fiber laser transmitter in 200 ns regime with transform-limited linewidth, leveraging on NP's proprietary germanate active fibers. NP's patented large core SM PM highly Tm-doped germanate glass fibers have high unit gain and high stimulated Brillouin scattering (SBS)-threshold. We will use our proprietary single-frequency actively Q-switched fiber laser seed in order to make the whole high power narrow linewidth pulsed fiber laser transmitter compact and expandable to spaceborne or UAV platforms. In Phase I, one new SM PM highly Tm-doped germanate fiber with 25 micron core will be fabricated and used for the power amplifier stage in order to demonstrate 1-5 mJ pulse energy and ~ 10 kW peak power for 200 ns fiber laser pulses with SBS-free. In Phase II, 100 micron core germanate fiber will be designed and fabricated in order to demonstrate 50 mJ fiber laser pulses with 100's kW SBS-threshold and transform-limited linewidth. In this project, NP Photonics will offer prototype/product service to NASA by delivering 1-50 mJ monolithic 2 micron pulsed fiber laser transmitter in 200 ns regime with transform-limited linewidth.