High Energy Laser (HEL) Beam Combination

Diode-pumped fiber lasers have been shown to be extremely compact, rugged and efficient, with output powers of 200 Watts to over 1 kWatt 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. In Phase I, we advanced the modeling and fabrication techniques for such an output coupler and proposed an individual fiber laser architecture that has inherent benefits for incorporation in multi-element arrays. A model for predicting the stability and robustness of up to a 7-element array of close packed fibers was developed and used to select a design that shows robust locking for 4 fiber lasers. In this Phase II effort we plan to build and test this 4-element laser system and to use the knowledge gained in this effort to model and propose higher fiber count systems that can be scaled up to 100 kWatt.