26-mJ pulse energy Q-switched large-pitch fiber laser system with excellent beam quality

Florian Jansen; Fabian Stutzki; Andreas Liem; Cesar Jauregui; Jens Limpert; Andreas Tünnermann

doi:10.1117/12.908261

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15 February 2012 26-mJ pulse energy Q-switched large-pitch fiber laser system with excellent beam quality

Florian Jansen, Fabian Stutzki, Andreas Liem, Cesar Jauregui, Jens Limpert, Andreas Tünnermann

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Proceedings Volume 8237, Fiber Lasers IX: Technology, Systems, and Applications; 82371S (2012) https://doi.org/10.1117/12.908261
Event: SPIE LASE, 2012, San Francisco, California, United States

Abstract

In this work we report on what we believe is the highest pulse energy obtained from an effectively single-mode Qswitched fiber laser system to date. This result has been obtained using rare-earth-doped double-clad large-pitch fibers which are able to delocalize the higher-order transverse modes from the active region of the core. We have built an actively Q-switched oscillator consisting of a 1.3m long large-pitch fiber with a mode field diameter of 50μm. This oscillator delivered pulses with 500μJ energy at a repetition rate of 5kHz. These seed pulses have been amplified in two fiber amplifiers which were pumped at 976nm. The pre-amplifier employs a 1.2m long large-pitch fiber with a mode field diameter of 80μm and delivered 3.5mJ pulse energy. Then, a 135μm core diameter large-pitch fiber was used as booster amplifier. Under high power operation the mode field diameter of this fiber is ~100μm. The setup can deliver average powers of up to 130W, resulting in 26mJ pulses with pulse durations of ~50ns. Additionally, since this is an effective single-mode laser system, the beam quality is close to the diffraction-limit.

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Florian Jansen, Fabian Stutzki, Andreas Liem, Cesar Jauregui, Jens Limpert, and Andreas Tünnermann "26-mJ pulse energy Q-switched large-pitch fiber laser system with excellent beam quality", Proc. SPIE 8237, Fiber Lasers IX: Technology, Systems, and Applications, 82371S (15 February 2012); https://doi.org/10.1117/12.908261

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