TY - JOUR

T1 - Thermal Effects on the Single-Mode Regime of Distributed Modal Filtering Rod Fiber

A1 - Coscelli,Enrico

A1 - Poli,Federica

A1 - Alkeskjold,Thomas Tanggaard

A1 - Jørgensen,Mette Marie

A1 - Leick,Lasse

A1 - Broeng,Jes

A1 - Cucinotta,Annamaria

A1 - Selleri,Stefano

AU - Coscelli,Enrico

AU - Poli,Federica

AU - Alkeskjold,Thomas Tanggaard

AU - Jørgensen,Mette Marie

AU - Leick,Lasse

AU - Broeng,Jes

AU - Cucinotta,Annamaria

AU - Selleri,Stefano

PB - I E E E

PY - 2012

Y1 - 2012

N2 - Power scaling of fiber laser systems requires the development of innovative active fibers, capable of providing high pump absorption, ultralarge effective area, high-order mode suppression, and resilience to thermal effects. Thermally induced refractive index change has been recently appointed as one major limitation to the achievable power, causing degradation of the modal properties and preventing to obtain stable diffraction-limited output beam. In this paper, the effects of thermally induced refractive index change on the guiding properties of a double-cladding distributed modal filtering rod-type photonic crystal fiber, which exploits resonant coupling with high-index elements to suppress high-order modes, are thoroughly investigated. A computationally efficient model has been developed to calculate the refractive index change due to the thermo-optical effect, and it has been integrated into a full-vector modal solver based on the finite-element method to obtain the guided modes, considering different heating conditions. Results have shown that the single-mode regime of the distributed modal filtering fiber is less sensitive to thermal effects with respect to index-guiding fibers with the same effective area. In fact, as the pump power is increased, their single-mode regime is preserved, being only blue-shifted in wavelength.

AB - Power scaling of fiber laser systems requires the development of innovative active fibers, capable of providing high pump absorption, ultralarge effective area, high-order mode suppression, and resilience to thermal effects. Thermally induced refractive index change has been recently appointed as one major limitation to the achievable power, causing degradation of the modal properties and preventing to obtain stable diffraction-limited output beam. In this paper, the effects of thermally induced refractive index change on the guiding properties of a double-cladding distributed modal filtering rod-type photonic crystal fiber, which exploits resonant coupling with high-index elements to suppress high-order modes, are thoroughly investigated. A computationally efficient model has been developed to calculate the refractive index change due to the thermo-optical effect, and it has been integrated into a full-vector modal solver based on the finite-element method to obtain the guided modes, considering different heating conditions. Results have shown that the single-mode regime of the distributed modal filtering fiber is less sensitive to thermal effects with respect to index-guiding fibers with the same effective area. In fact, as the pump power is increased, their single-mode regime is preserved, being only blue-shifted in wavelength.

KW - Fiber lasers

KW - Optical fibers

KW - Photonic crystal fibers

KW - Thermooptic effects

U2 - 10.1109/JLT.2012.2222350

DO - 10.1109/JLT.2012.2222350

JO - Journal of Lightwave Technology

JF - Journal of Lightwave Technology

SN - 0733-8724

IS - 22

VL - 30

SP - 3494

EP - 3499

ER -