SBIR-STTR Award

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.

Keywords:
HIGH POWER LASER, COHERENT COMBINING, SELF-ORGANIZATION, FIBER LASER, OPTICAL FIBER, OPTICAL FIBER COMBINER, FUSED TAPERERED COUPLER

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.

Keywords:
High Power Laser, Fiber Laser, Beam Combining, Coherent Combining, Self-Organization, Optical Fiber Coupler, Photonic Crystal Fiber, Fused Tapered Cou