Large Mode Area Yb-doped Photonic Bandgap Fiber Lasers

Fiber lasers are in the process of revolutionizing modern manufacturing. Further power scaling is still much desired to increase throughput and to break new frontiers in science and defense. It has become very clear now that highly single-mode fibers with large effective mode areas are required to overcome both nonlinear effects and mode instability [1-3]. We have been studying all-solid photonic bandgap fibers (AS-PBF), which have open and highly dispersive cladding, making them ideal for higher-order-mode controls in large-mode-area fibers. I will review our recent progress in this area and, especially in ytterbium-doped AS-PBF lasers and amplifiers.