Comparative study of light propagation and single-mode operation in large-mode area fibers designed for 2-μm laser applications

Abstract. Output performances of fiber-based optical systems, in particular fiber lasers and amplifiers, can be controlled using tailored fiber designs, gain profiles, and pump light overlap with the gain medium. Here, the performances of 2-μm light, propagating in three large-mode area fibers, a step-index fiber, a photonic crystal fiber (PCF), and a leakage channel fiber (LCF), designed to deliver a single-mode (SM) beam at this wavelength, were compared. Using the S2 imaging technique, the transverse mode content has been decomposed, and propagation losses, SM purity, and mode-field area (MFA) were measured for various input mode overlap and coiling diameters. It was experimentally demonstrated that coiling the PCF and LCF to 40 and 20 cm in diameter, respectively, resulted in efficient higher-order mode suppression, pure SM beam delivery, moderate (∼1  dB) coil-induced losses in the fundamental mode, and nondistorted, large MFA (∼1600  μm2) beam delivery.

[1]  Martin Richardson,et al.  Comparison of higher-order mode suppression and Q-switched laser performance in thulium-doped large mode area and photonic crystal fibers. , 2012, Optics express.

[2]  B. Hafizi,et al.  Incoherent Combining and Atmospheric Propagation of High-Power Fiber Lasers for Directed-Energy Applications , 2009, IEEE Journal of Quantum Electronics.

[3]  Daniel Flamm,et al.  Detailed Characterization of Optical Fibers by Combining $\bm S^{\bf 2}$ Imaging With Correlation Filter Mode Analysis , 2014, Journal of Lightwave Technology.

[4]  Nathaniel M Fried,et al.  Thulium fiber laser lithotripsy: An in vitro analysis of stone fragmentation using a modulated 110‐watt Thulium fiber laser at 1.94 µm , 2005, Lasers in surgery and medicine.

[5]  J. Cariou,et al.  Laser source requirements for coherent lidars based on fiber technology , 2006 .

[6]  Farzin Amzajerdian,et al.  High-energy 2μm Doppler lidar for wind measurements , 2007 .

[8]  B. Samson,et al.  Tm-Doped Fiber Lasers: Fundamentals and Power Scaling , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

[9]  Cesar Jauregui,et al.  High-power very large mode-area thulium-doped fiber laser. , 2012, Optics letters.

[10]  Cesar Jauregui,et al.  Temporal dynamics of mode instabilities in high-power fiber lasers and amplifiers. , 2012, Optics express.

[11]  A. E. Siegman,et al.  How to (Maybe) Measure Laser Beam Quality , 1998 .

[12]  Min Jiang,et al.  Mid-infrared ZnGeP2 parametric oscillator directly pumped by a pulsed 2 microm Tm-doped fiber laser. , 2008, Optics letters.

[13]  J W Nicholson,et al.  Spatially and spectrally resolved imaging of modal content in large-mode-area fibers. , 2008, Optics express.

[14]  J. Fini,et al.  Measuring the Modal Content of Large-Mode-Area Fibers , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

[15]  Dietrich Marcuse,et al.  Field deformation and loss caused by curvature of optical fibers , 1976 .

[16]  S. Setzler,et al.  Mid-infrared ZnGeP2 parametric oscillator directly pumped by a pulsed 2 microm Tm-doped fiber laser. , 2008, Optics letters.

[17]  B. Ward,et al.  Origin of thermal modal instabilities in large mode area fiber amplifiers. , 2012, Optics express.

[18]  Martin Richardson,et al.  CW-lasing and amplification in Tm(3+)-doped photonic crystal fiber rod. , 2012, Optics letters.

[19]  J. Limpert,et al.  Improved Modal Reconstruction for Spatially and Spectrally Resolved Imaging $({\rm S}^{2})$ , 2013, Journal of Lightwave Technology.

[20]  Martin Richardson,et al.  Lasing in thulium-doped polarizing photonic crystal fiber. , 2011, Optics letters.

[21]  S. Wielandy,et al.  Implications of higher-order mode content in large mode area fibers with good beam quality. , 2007, Optics express.

[22]  R. Schermer,et al.  Mode scalability in bent optical fibers. , 2007, Optics express.

[23]  Liang Dong,et al.  Ytterbium-doped all glass leakage channel fibers with highly fluorine-doped silica pump cladding. , 2009, Optics express.

[24]  C Molardi,et al.  Thermally resilient Tm-doped large mode area photonic crystal fiber with symmetry-free cladding. , 2014, Optics express.

[25]  Martin Richardson,et al.  High-power widely tunable thulium fiber lasers. , 2010, Applied optics.

[26]  Yulong Tang,et al.  High-power narrow-bandwidth thulium fiber laser with an all-fiber cavity. , 2012, Optics express.