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Ultrabroadband amplification and two-color CW lasing simultaneously near 1.9 μm and 2.3 μm in a Tm3+-doped tellurite fiber were demonstrated experimentally, for the first time to the best of our knowledge. A low-loss Tm3+-doped core fiber from TeO2-ZnO-La2O3-Na2O glasses stable against crystallization was produced by a special technique, providing a low concentration of hydroxyl groups. Supercontinuum from a highly GeO2 doped silica fiber pumped by an Er fiber laser system was used as a seed for an amplifier. A maximum gain of 30 dB and 7 dB was measured at 1.9 μm and 2.3 μm, respectively. We report detailed experimental and theoretical studies, which are in a very good agreement, of laser amplification and generation in the manufactured fiber with carefully measured and calculated parameters. A quantitatively verified numerical model was used to predict power scalability at 2.3 μm in schemes with optimized parameters at increased pump power. The presented results show that a high-quality tellurite fiber is a promising candidate for developing lasers in the 2.3 μm atmospheric window which are particularly relevant for applications in gas sensing, eye-safe laser radars, breath analysis, remote sensing and stand-off trace gas detection. [ABSTRACT FROM AUTHOR]

An all-fiber high-power erbium-doped fiber laser (EDFL) source generating optical pulses from 200 µs to 5 ms with a stable rectangular envelope for fractional photo-rejuvenation is proposed and experimentally demonstrated. A master oscillator power amplifier (MOPA) configuration composed of a master oscillator, an acousto-optic modulator (AOM), and a one-stage amplifier is designed and employed in the EDFL to serve as an efficient laser system with excellent output performance. To avoid multistage amplifiers, the master oscillator generates 1.5 W, and a Yb-free Er-doped large-mode-area (LMA) active fiber is used for a one-stage power amplifier. There are two benefits to this approach: first, modulation of both pump and seed pulses is used to achieve clear rectangular shaped pulses without amplified spontaneous emission (ASE) growth; and second, there are no power limitations in the amplifier and undesirable 1 µm ASE compared to Er/Yb systems. We have reached 28.6 W of peak power with 26% slope efficiency limited only by available pump power, so the system can be easily scaled for achieving a higher peak power.

We report generation of femtosecond optical pulses tunable in the 1.6-2.5 μm range using GeO2-doped core silica-cladding fibers. Optical solitons with a duration of 80-160 fs have been measured by the FROG technique in the 2-2.3 μm range. To the best of our knowledge, these are the longest wavelength temporally characterized solitons generated in silica-based fibers. We have also demonstrated more than octave-spanning femtosecond supercontinuum generation in the 1.0-2.6 μm range.

We report a simple all-fiber design of an Er-doped laser system that is capable of generating widely tunable two-cycle pulses. In particular, 13-fs pulses at a wavelength of 1.7 μm are produced. The mechanism of pulse shortening is identical to the higher-order soliton compression and is supported by modeling based on the slowly evolving wave approximation, which is well suited for down to single-cycle pulse propagation in nonlinear dispersion-shifted fibers.