Efficient low-brightness-pumped Raman amplification of a single high-order Bessel mode in 335-m of 70-µm-diameter silica-core step-index fiber
Abstract
We experimentally demonstrate Raman amplification of signal pulses in a high-order Bessel mode ( L P 06 ) at a wavelength of 1121 nm in a 335-m step-index fiber with a 70-µm diameter, 0.227-NA pure-silica core. This was pumped by 5-ns multimode pulses at 1065 nm from a Yb-doped fiber master oscillation power amplifier. The mode purity of the amplified pulses is well preserved to 23 dB of average-power gain, to 774 W of peak power in 2 ns pulses at a 20 kHz repetition rate, when pumped with a peak power of 942 W. The pump depletion as averaged over the signal pulses reaches 59%. We believe, to the best of our knowledge, that this is the first demonstration of stable mode propagation and Raman amplification of a single Bessel-like higher-order mode in a fiber of hundreds of meters. This shows the potential for efficient power scaling of a single signal mode with low-brightness pumping, comparable with that from continuous-wave multimode diode lasers.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 27, 2020
- Source ID
- 10.1364/ol.404602
Entities
People
- Johan Nilsson
- P. Barua
- Sheng Zhu
- Yutong Feng
Organizations
- Air Force Office of Scientific Research