Symmetry-free tm-doped photonic crystal fiber with enhanced mode area

Enrico Coscelli, Carlo Molardi, Annamaria Cucinotta, Stefano Selleri

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Thulium-doped fiber lasers have recently attracted a growing interest because of the possibility to combine emission around 2 $\mu$m with the high beam quality and compactness provided by the fiber medium. A key factor for power scaling of these devices, especially if operation in the short-and ultrashort-pulse regime is desired, is the availability of active fibers capable of joining large effective area and robust single-mode guiding. The strong thermo-optic effect originating from the large quantum defect of Tm ions hinders the possibility to easily find a design with such features, strongly improving the confinement of high-order modes and shrinking the mode area of the fundamental one. In this paper, a rod-type double-cladding photonic crystal fiber with inner cladding properly designed without any mirror symmetry in the cross-section is presented, and its guiding properties are thoroughly analyzed by means of numerical simulations, taking into account the effects of thermally-induced refractive index change. The results have shown that, with a careful choice of the structural parameters, the proposed fiber is capable of ensuring effective high-order mode suppression and effective area up to 3800 2 when operating under heat load of about 300 W/m.

Original languageEnglish
Article number6709780
JournalIEEE Journal on Selected Topics in Quantum Electronics
Issue number5
Publication statusPublished - Sep 1 2014
Externally publishedYes


  • Double-cladding photonic crystal fibers
  • single-mode regime
  • thulium-doped fibers

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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