Rapid, electronically controllable transverse mode selection in a multimode fiber laser

Abstract

A novel technique for the electronically-controllable generation and switching of transverse modes within a multi-mode fiber laser oscillator is presented. Preliminary results demonstrate individual transverse mode lasing and fast switching between modes with watt-level output powers. When applied to a core-pumped Tm-doped silica fiber laser with a multimode core the fundamental mode (LP 01 ), the next higher order mode (LP 11 ), or a donut-shaped LP 11 superposition were selectively excited with power levels in excess of 5 W. Fast switching between LP 01 and LP 11 modes at up to 20kHz was also realized. 19173-19179 (2013). 3. J. Limpert, F. Stutzki, F. Jansen, H.-J. Otto, T. Eidam, C. Jauregui, and A. Tünnermann, "Yb-doped large-pitch fibres: effective single-mode operation based on higher-order mode delocalisation," Light Sci.

Functional Fibers and Functional Fiber-Based Components for High-Power Lasers

“…8b. Consequently, CT-FBGs are considered to provide great potential for broadband fiber filters [391,392].…”

High-power fiber laser with real-time mode switchability

“…In fact, there are several approaches to realizing mode adjusting/switching in fiber lasers [12] , and technically an 'optical switch' combined with mode selective components should be adopted. The mode switching/adjusting operation could either be realized by real optical components, such as acoustic-optic tunable filter (AOTF) [13] , special fiber coupler [14][15][16][17] , acoustically induced fiber grating (AIFG) [18][19][20][21] , polarization controller (PC) [22][23][24][25][26][27] , and spatial light modulator [28] , or by some physical mechanisms, such as temperature control of few-mode fiber Bragg gratings (FBGs) [29] , altering the excitation condition [30] , and injection locking [31] . However, fast mode switching between different transverse modes in fiber lasers has only been demonstrated using AOTF and AIFG.…”

“…However, fast mode switching between different transverse modes in fiber lasers has only been demonstrated using AOTF and AIFG. In 2013, Daniel et al demonstrated a 5-W-level mode switchable Tm-doped fiber laser operating around 1921 nm, where the mode switching between the LP 01 and LP 11 modes is realized by an AOTF and a few-mode fiber grating [13] . The whole system was based on a bulk configuration, and the mode switching speed reached an approximately kilohertz (kHz) level.…”

All-Fiber Laser With Agile Mode-Switching Capability Through Intra-Cavity Conversion

“…Meanwhile, the fast-mode switching capability can enable the use of the optimum beam characteristics for each step of the cutting process, not just for cutting of different materials or various thicknesses [16]- [19]. In 2013, J. Daniel et al realized mode selection and switching in a multimode fiber laser oscillator by adopting a few-mode fiber Bragg grating and an acoustic-optic tunable-filter as the free-space wavelength-selective element [18]. They proved that the mode is changing at the frequency of 20 kHz but could not confirm that it was switching between LP 01 and LP 11 modes.…”