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Lasers and Optics Diode-pumped 200 Μm Diameter Core, Gain-guided, Index-antiguided Single Mode Fiber Laser
| Content Provider | Semantic Scholar |
|---|---|
| Author | Physics, Applied Mccomb, T. Chen, Yin |
| Copyright Year | 2008 |
| Abstract | Single mode laser action in a diode-pumped gain-guided, index-antigu-ided Nd 3+-doped phosphate glass fiber having a 200-µm-diameter core is demonstrated. Near-Gaussian beam quality was maintained, even when pumped up to four times the threshold pump power, indicating robust lowest order mode oscillation. Subtle differences associated with the effectiveness of diode pumping gain-guided, index-antiguided fibers are discussed. 1 Introduction High power fiber lasers and amplifiers have many potential applications in the commercial and the defense arenas. The principal limitations to high powers in conventional single-mode fibers are the onset of nonlinear optical effects (stimulated Brillouin and Raman scattering) and catastrophic optical damage in the core and at the fiber end facets. These limitations can be avoided with the use of multiple beam combining techniques or through the design of large mode area (LMA) fibers that increase the size of the core without compromising the near diffraction limited beam quality of the fiber. Single mode fiber lasers have been demonstrated with conventional step-index LMA fibers with maximum core diameters up to 40 µm [1]. Photonic crystal fibers with core sizes up to 100 µm have allowed single mode laser operation [2, 3]. However, beyond this core diameter, near diffraction limited beam quality is difficult to maintain. To investigate the potential of further increasing the size of the core and yet maintaining the single-mode characteristic , other approaches are being pursued. One method involves exciting a single higher-order mode (HOM) with very high modal purity in an appropriately designed fiber that will support only a few modes, thereby ensuring that the modal stability of the HOM is greater than that of the fundamental mode [4]. Another approach uses chirally coupled core (CCC) fibers that offer design flexibility by selectively leaking HOMs through one or more helical satellite cores wrapped around the central core [5]. Yet, even so, these approaches have not involved core sizes > 100 µm. Bend-loss management or tapered fiber sections can also be used to filter out higher-order modes. Koplow et al. [6] showed that the bend-loss technique becomes less effective for larger-core fibers. Higher order mode suppression in a 100-µm-core fiber is at least a factor of 10 lower than that observed in more commonly used 25–50 µm core fibers. The use of tapers is also possible, but these not only filter out HOMs, they also limit output power [7]. Another approach to scaling the core size of the … |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.stanford.edu/~siegman/index_antiguided_fiber_lasers/2008%20CREOL%20Diode%20pumped%20200%20um%20AP%20B%20Feb.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Amplifier Brillouin scattering Clipping (computer graphics) Compositing Core (optical fiber) Core needle biopsy Decade (log scale) Diameter (qualifier value) Diffuse Large B-Cell Lymphoma Diode Device Component Diode–transistor logic Dots per inch Fiber laser Image scaling Lasers Modal logic Nonlinear system Norm (social) Normal Statistical Distribution Normal mode Onset (audio) Power (Psychology) Pumping (computer systems) Pure function Raman scattering Tapering - action Test scaling Tissue fiber Zero suppression fiberglass inorganic phosphate pump (device) |
| Content Type | Text |
| Resource Type | Article |
