title: Pulsed operation of a resonantly pumped, linearly polarised, large mode area holmium-doped fibre amplifier.
abstract: We present the design of a polarisation maintaining, resonantly and cladding pumped, large mode area holmium-doped fibre. We describe the operation of this fibre in a pulsed amplifier configuration. The amplifier produced pulses with energy of 2.25 mJ and duration of 20 ns at a repetition rate of 20 kHz and average power of 45 W. The holmium-doped fibre provided >10 dB of gain at 2.09 µm and the polarisation extinction ratio was >11.5 dB. The beam quality of the output (M2) was 1.6. To the best of our knowledge this is the highest pulse energy achieved from any singly holmium-doped fibre by an order of magnitude.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hemming
authors.forename: Jim
authors.initials: J
authors.lastname: Richards
authors.forename: Nikita
authors.initials: N
authors.lastname: Simakov
authors.forename: Alan
authors.initials: A
authors.lastname: Davidson
authors.forename: Neil
authors.initials: N
authors.lastname: Carmody
authors.forename: John
authors.initials: J
authors.lastname: Haub
authors.forename: Adrian
authors.initials: A
authors.lastname: Carter