No abstract

We report a compact multicore fiber laser that utilizes an all-fiber approach for phase locking and in-phase supermode selection. By splicing passive coreless fibers of controlled lengths to both ends of an active 19-core fiber, we demonstrate that the fundamental in-phase supermode can be selectively excited with a completely monolithic fiber device, instead of conventional free-space and bulk optics, to achieve phase-locked operation for a multiemitter laser device.

We generate as much as 1.6 W of continuous-wave 1550 nm single-longitudinal-mode output from a cladding pumped Er-Yb codoped phosphate fiber laser. This power is to our knowledge among the highest in single-longitudinal-mode fiber lasers. The narrowband fiber Bragg grating output coupler is demonstrated to be an effective element for providing the single-longitudinal-mode selection.

A method of generating nondiffracting beams using multimode optical fibers is reported. When a large-core multimode fiber is spliced onto a piece of single-mode fiber, only linearly polarized (LP0,n) modes are excited inside the multimode fiber segment because of mode orthogonality and on-axis excitation. Since the excited LP0,n modes are actually Bessel fields with different transverse wave vectors truncated by the core of the multimode fiber, the beam exiting the multimode fiber facet can form a variety of readily controllable and nearly nondiffracting optical patterns resulting from interference of apertured Bessel fields.