YQI SSO Talk - Darcy Smith - Adelaide University

Title: Multimode fibers for power scaling and the suppression of nonlinear effects in high-power fiber amplifiers
Abstract:

Fiber lasers and amplifiers have been shown to achieve high optical powers with excellent beam quality, enabling applications in both fundamental science and industry. This excellent beam quality has been predominantly obtained through single mode operation, however single mode fiber lasers are beginning to reach hard limits on power scaling due to the onset of nonlinear effects at high power. Multimode fibers (MMFs) offer inherently higher nonlinear effect thresholds, enabling further power scaling, but with significantly reduced beam quality.

Advanced wavefront-shaping techniques leverage deterministic propagation through an MMF to produce a potentially near-diffraction-limited spot at the fiber output through optimization of the input wavefront. A demonstration of wavefront shaping techniques applied to a high-power, 1550 nm pulsed Er/Yb fiber amplifier system will be presented, along with record peak-power results from a fiber amplifier at 1550 nm. Additionally, a novel MMF amplifier model will be presented, demonstrating the ability to model multimode dynamics in a MMF amplifier to a greater degree of accuracy than current literature.