Single transverse mode Yb-doped fiber laser generating several 100 µJ with flexible pulse parameters

Tim Lauterborn, Stefan Heinemann and A. Galvanauskas

Fraunhofer USA, Center for Laser Technology, 46025 Port Street, Plymouth, MI 48170, P: 734 354 6300 x. 203, F: 734 354 3335, tlauterborn@clt.fraunhofer.com

Abstract:

We demonstrate a pulsed single transverse mode Yb-doped fiber laser that can be operated in a wide range of pulse lengths and repetition rates.

The pulsed 1064 nm beam of a single mode diode laser is amplified by a three stage fiber amplifier. It consists of two pre-amplification stages that incorporate single-mode fibers. The third stage is made from a LMA fiber with different core sizes. A monolithic setup is achieved by a taper between the pre-amplification stages and the core LMA fiber of the third stage exciting only the fundamental mode in the LMA fiber. The different setups are experimentally tested to evaluate maximum pulse energy and peak power.

Variable pulse regimes were investigated with a maximum output energy of several 100 µJ at repetition rates in the range from 1 kHz to 1 MHz. An average output power of 6 W was measured at 8 ns pulse length and 100 kHz repetition rate.

Pulse trains of four pulses at repetition rates of the train of 1 kHz and pulse spacing of 200, 500 and 1000 ns were also investigated. The pulse length was set to 10 ns.

Different system concepts will be presented and their suitability for LIDAR will be discussed.