High-power mid-infrared frequency comb source based on a femtosecond Er:fiber oscillator.

We report on a high-power mid-infrared (MIR) frequency comb source based on a femtosecond (fs) Er:fiber oscillator with a stabilized repetition rate of 250 MHz. The MIR frequency comb is produced through difference frequency generation in a periodically poled MgO-doped lithium niobate crystal. The output power is about 120 mW, with a pulse duration of about 80 fs and spectrum coverage from 2.9 to 3.6 µm, and the single comb mode power is larger than 0.3 µW over the range of 700 nm. The coherence properties of the produced high-power broadband MIR frequency comb are maintained, which was verified by heterodyne measurements. As the first application, the spectrum of a ~200 ppm methane-air mixture in a short 20 cm glass cell at ambient atmospheric pressure and temperature was measured.

0.7W all-fiber Erbium oscillator generating 64 fs wave breaking-free pulses.

We report on the generation of wave breaking-free pulses from a passively mode-locked all-fiber Erbium oscillator at 1.55 microm pumped by a Raman fiber assembly operating at 1.48 microm. The extracted pulses show a self-similar behaviour and can be scaled up to an average power of 675 mW only limited by the pump power. The laser operates at the fundamental repetition rate of 108 MHz, therefore the pulse energy is 6.2 nJ. After external compression, the dechirped pulse duration is 64 fs.

Phase-locked carrier-envelope-offset frequency at 1560 nm.

We report on the measurement of an Erbium-fiber oscillator's carrier-envelope-offset frequency using an extruded SF6 photonic crystal fiber for the generation of a more than two octave-spanning supercontinuum from 400 nm to beyond 1750 nm. A modified type of f-2f-interferometer was employed, beating the frequency doubled input signal of the fiber oscillator with the supercontinuum to generate the carrier-envelope-offset beat. Controlling the fiber oscillator's pump power with an electronic feedback loop, we phase-locked the carrier-envelope-offset frequency to an external reference source. The resulting residual phase excursions correspond to fractional frequency instabilities of the oscillator's frequency comb of the order of 10(-16) for averaging times longer than 10 s.

Stable sub-85 fs passively mode-locked Erbiumfiber oscillator with tunable repetition rate.

We present a sub-85 fs self-starting stretched-pulse passively mode-locked Erbium-fiber oscillator in a sigma setup with tunable repetition rate. The sigma cavity included a movable mirror enabling a tunable pulse repetition rate variation of +/- 1 % from 55.3 MHz to 56.4 MHz with continuous, uninterrupted mode-locked operation and an output power around 14 mW. Based on the wide tuning range of the repetition rate the presented fiber oscillator is a suitable candidate for applications in femtosecond spectroscopy or precision metrology around 1.56 microm.

Supercontinuum generation with 200 pJ laser pulses in an extruded SF6 fiber at 1560 nm.

We report an all-fiber diode-pumped Erbium-fiber oscillator-amplifier system as a source for supercontinuum generation in a photonic crystal fiber at 1560 nm. The passively mode-locked oscillator-amplifier system provides linearly polarized output pulses of 60 fs and an average output power of 59 mW at a repetition rate of 59.1 MHz. The laser pulses were launched into an extruded SF6-fiber for generation of an ultra-broadband supercontinuum. The evolution of the supercontinuum as a function of launched pulse energy was investigated. With pulse energies of about 200 pJ we observed a more than octave-spanning supercontinuum from 400 nm to beyond 1750 nm.