We report an all-fiber passively Q-switched laser using a large mode area (LMA) Yb³⁺ -doped fiber claddingpumped at 915 nm and an unpumped single-mode (SM) Yb3⁺-doped fiber as the saturable absorber (SA). The saturable absorber SM fiber and LMA gain fiber were coupled with a fiber taper designed to match the fundamental spatial mode of the LMA fiber and the expanded LP01 mode of the single mode fiber. The amplified spontaneous (ASE) intensity propagating in the single mode SA saturates the absorption before the onset of gain depletion in the pumped fiber, switching the fiber cavity to a high Q-state and producing a pulse. Using this scheme we demonstrate a Q-switched all-fiber oscillator with 32 μJ 93 ns pulses at 1030 nm. The associated peak power is nearly two orders of magnitude larger than that reported in previous experimental studies using a single Yb⁺³ saturable absorber fiber. The pulse energy was amplified to 0.230 mJ using an Yb³⁺-doped cladding pumped fiber amplifier fusion spliced to the fiber oscillator, increasing the energy by eight fold while preserving the all-fiber architecture.

Date Published: 7 March 2014
PDF: 4 pages
Proc. SPIE 8961, Fiber Lasers XI: Technology, Systems, and Applications, 896113 (7 March 2014); doi: 10.1117/12.2040813

Published in SPIE Proceedings Vol. 8961:
Fiber Lasers XI: Technology, Systems, and Applications
Siddharth Ramachandran, Editor(s)