Novel Techniques to Combine Optical Radiation from Fiber Lasers

Diode-pumped fiber lasers have been shown to be extremely compact, rugged and efficient, with output powers of 200 Watts to over 2 kWatts demonstrated. It has also been demonstrated that an array of individual fiber lasers can self-organize coherently with appropriate connectivity or "cross-coupling" at the output. This effect is completely passive, without the need for active phase, polarization or amplitude control, and can be achieved with an appropriately designed all-fiber output coupler. The technical objective of this Phase I proposal is to advance the design, modeling and fabrication techniques required for the production of such an optical fiber coupler, and to propose and model the architecture required for implementation of such a high-power laser system. This work will lay the foundation for a Phase II effort that will focus on implementing the designs and techniques developed in Phase I, with the goal of achieving stable, robust coherent combining of high-count fiber laser arrays, with the potential for acheiving an output power of 100 kWatts.