Nanosecond laser damage of optical multimode fibers

For pulse laser materials processing often optical step index and gradient index multimode fibers with core diameters ranging from 100 to 600 μm are used. The design of a high power fiber transmission system must take into account limitations resulting from both surface and volume damage effects. Especially, breakdown at the fiber end faces and selffocusing in the fiber volume critically influence the fiber performance. At least operation charts are desirable to select the appropriate fiber type for given laser parameters. In industry-relevant studies the influence of fiber core diameter and end face preparation on laser-induced (surface) damage thresholds (LIDT) was investigated for frequently used all-silica fiber types (manufacturer LEONI). Experiments on preform material (initial fiber material) and compact specimens (models of the cladding and coating material) accompanied the tests performed in accordance with the relevant LIDT standards ISO 21254-1 and ISO 21254-2 for 1-on-1 and S-on-1 irradiation conditions, respectively. The relation beam diameter vs. LIDT was investigated for fused silica fibers. Additionally, laser-induced (bulk) damage thresholds of fused silica preform material F300 (manufacturer Heraeus) in dependence on external mechanical stress simulating fiber bending were measured. All experiments were performed with 10-ns laser pulses at 1064 and 532 nm wavelength with a Gaussian beam profile.

[1]  J. Krüger,et al.  Breakdown limits of optical multimode fibers for the application of nanosecond laser pulses at 532 nm and 1064 nm wavelength , 2009 .

[2]  G. Mourou,et al.  Femtosecond Optical Breakdown in Dielectrics , 1998 .

[3]  B. Do,et al.  Bulk and surface laser damage of silica by picosecond and nanosecond pulses at 1064 nm. , 2008, Applied optics.

[4]  Gerard Mourou,et al.  Laser‐induced breakdown by impact ionization in SiO2 with pulse widths from 7 ns to 150 fs , 1994 .

[5]  Dieter Bäuerle,et al.  Laser processing and chemistry: recent developments , 2002 .

[6]  J. Krüger,et al.  Influence of core diameter and coating material on nanosecond laser-induced damage threshold of optical multimode fibers , 2010 .

[7]  Perry,et al.  Laser-induced damage in dielectrics with nanosecond to subpicosecond pulses. , 1995, Physical review letters.

[8]  S. R. Foltyn.  Spotsize effects in laser damage testing , 1982 .

[9]  Jörg Krüger,et al.  Beam diameter dependence of surface damage threshold of fused silica fibers and preforms for nanosecond laser treatment at 1064 nm wavelength , 2013 .

[10]  P. Simon,et al.  Nanosecond and femtosecond excimer laser ablation of fused silica , 1992 .

[11]  N. Sanner,et al.  Influence of the beam-focus size on femtosecond laser-induced damage threshold in fused silica , 2008, SPIE LASE.

[12]  M. Jupé,et al.  Scaling law investigations in spot sizes dependence in the ns regime , 2006, SPIE LASE.

[13]  M. Niemz.  Threshold dependence of laser‐induced optical breakdown on pulse duration , 1995 .

[14]  J. Krüger,et al.  Influence of mechanical stress on nanosecond laser-induced damage threshold of fused silica , 2012 .

[15]  J. Krüger,et al.  Nanosecond laser-induced surface damage of optical multimode fibers and their preforms , 2008 .

[16]  J. Krüger,et al.  Nanosecond laser damage resistance of differently prepared semi-finished parts of optical multimode fibers , 2007 .