Single-crystal fiber optical devices: a ND:YAG fiber laser

Single−crystal fibers of Nd:YAG have been grown in diameters as small as, but not limited to, 50 μm by a pedestal growth (modified zone melting) technique. Room−temperature cw laser operation has been achieved with 0.5−1−cm−long samples. The method is directly applicable to the growth of single−crystal fibers of various materials for devices covering a wide range of applications, especially for optical communications.