NKT Photonics has introduced a new version of its Crystal Fibre series of double-clad rod type fibres. The DC-285/100-PM-Yb-ROD is based on the company's patented airclad technology and features a strictly single-mode, polarisation-maintaining 100µm core with high absorption and low photodarkening. The Ytterbium doped rod is typically used in output stages of amplifier chains for high power pulsed laser amplification where it can sustain megawatt peak power levels.

The DC-285/100-PM-Yb-ROD fibre is polarisation maintaining and features a 76µm mode field diameter ytterbium core offering an effective mode field area of more than 4500µm2. The 285µm pump core diameter accepts pump light at numerical aperture values up to 0.55 for pumping at 915nm or 976nm. Pump absorption is 30dB/m for 976nm pumping.

Output of the rod fibre is robust single-transverse mode beam quality, and it has been tested with over 100W average power over a range of pulse durations and repetition rates.

The DC-285/100-PM-Yb-ROD fibre is designed for OEM use for industrial customers. It can be used as an extension of output energy levels for existing fibre amplifiers or as a replacement of traditional crystalline rods such as Nd:YAG, Nd:YVO4, Nd:YLF etc. Compared to such traditional laser rods, the rod fibre offers high beam quality guidance of the signal, as well as guidance of pump – without  thermal lensing. The rod fibre has a high single pass gain, PER of over 15dB and pump absorption is polarisation independent.