We report an all-fiber, high-power, low-noise amplifier system seeded by an all-normal-dispersion-mode-locked Ybdoped fiber laser oscillator. Up to 10.6 W of average power is obtained at a repetition rate of 43 MHz with diffraction-limited beam quality. Amplified pulses are dechirped to sub-160-fs duration in a grating compressor. It is to our knowledge the first high-power source of femtosecond pulses with completely fiber-integrated amplification comprising commercially available components. Longterm stability is excellent. Short-term stability is characterized and an integrated laser intensity noise of <0.2% is reported. We also conclude that all-normal dispersion fiber oscillators are low-noise sources, suitable as seed for fiber amplifiers. Detailed numerical modeling of both pulse generation in the oscillator and propagation in the amplifier provide very good agreement with the experiments and allow us to identify its limitations.

Intensity noise of mode-locked fiber lasers is characterized systematically for all major mode-locking regimes over a wide range of parameters. We find that equally low-noise performance can be obtained in all regimes. Losses in the cavity influence noise strongly without a clear trace in the pulse characteristics. Given that high-energy fiber laser oscillators reported to date have utilized large output coupling ratios, they are likely to have had high noise. Instabilities that occur at high pulse energies are characterized. Noise level is virtually independent of pulse energy below a threshold for the onset of nonlinearly induced instabilities. Continuous-wave peak formation and multiple pulsing influence noise performance moderately. At high energies, a noise outburst is encountered, resulting in up to 2 orders of magnitude increase in noise. These results effectively constitute guidelines for minimization of the laser noise in mode-locked fiber lasers.

Absorption spectroscopy is known to be a powerful tool to gain spatially and temporally resolved information on excited and reactive species in a plasma discharge. Furthermore, the interaction of the discharge with short intense laser pulses can trigger the ignition and the transition into other transient states of the plasma. In this context laser-assisted 'pump-probe' experiments involving simultaneously generated supercontinuum radiation yield highly temporally resolved and spatially well-defined information on the transient phenomena. In this paper we demonstrate the possibility for 'pump-probe' experiments by initiating breakdown on a picosecond time scale ('pump') with a high-power beam and measuring the broadband absorption with the simultaneously provided supercontinuum ('probe'). Since both pulses are generated from the same mode-locked master oscillator, they have a strong level of synchronization.

We report on characterization of the transfer of pump and seed signal modulations, including noise, during fiber amplification. We demonstrate experimentally and theoretically that pump (signal) modulations are transferred only below (above) a cut-off frequency.

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Pump modulation transfer function (MTF), and its dependence on pump power are investigated for all normal dispersion, dispersion managed and soliton-like mode-locked oscillator both in experiment and simulation. We find that cavity losses and pulse instabilities such as multiple pulsing influence noise transfer, strongly.

We investigate experimentally and theoretically the coupling of pump laser modulation and noise fluctuations to the output power of a fiber amplifier for broadband pulse trains using the modulation transfer function approach.

Transfer of fluctuations of pump power to laser power is characterized for mode-locked fiber oscillators. Contribution of pump noise to laser noise is estimated. Limits to pump modulation bandwidth for carrier-envelopephase stabilization are briefly discussed. ©2010 Optical Society of America Mode-locked fiber laser oscillators are intensely studied in recent years. The most common applications include generation of optical frequency combs [1] and seeding of fiber, solid-state or parametric amplifiers. Virtually for all applications and experiments, but particularly for optical frequency metrology and amplifier seeding, power fluctuations of the laser should be minimized. Recently, we have reported a systematic characterization of intensity noise of mode-locked fiber oscillators operating in different mode-locking regimes and over a range of laser parameters [2]. The noise of these lasers, although typically quite low (<0.1%), has significant contributions from technical noise, i.e., noise coupled from the environment or from the pump source. Since these can be eliminated with sufficient care, it is important to identify them. There is no systematic study, to our knowledge, of how fluctuations in pump power are transferred to laser noise.Here, we investigate how variations in pump power are coupled to the mode-locked laser power as a function of frequency and over a range of laser parameters. A modulation or noise transfer function (referred to as NTF from this point on) is experimentally measured. From this information, we can roughly estimate how much of the laser noise is stemming from the pump source, which turns out to be substantial. In addition, these transfer characteristics is important for intentional modulation of pump power, which is the standard technique for locking the carrier-envelope phase (CEP) in fiber-based frequency combs [1]. The mode-locked fiber laser is, of course, not a linear device. Therefore, a transfer function cannot describe its dynamics fully. Recognition of this fact, on a different note, motivates us to view measurements of NTF under different laser operation modes an informative probe into the laser dynamics especially under unusual operation modes. As an example, the NTF measurements are made for a laser in its normal operation as well as in a high-noise state that the laser we have recently identified [2]. An Yb-doped fiber laser (YDFL) and Er-doped fiber laser (EDFL) are used as test lasers. Mode-locking of both lasers is achieved by nonlinear polarization evolution. The YDFL operates in the similariton regime and EDFL operates in soliton-similariton regime, though the particular mode-locking regime is quite unlikely to alter the main results discussed here. The lasers are pumped in-core by a 980-nm pump diode with maximum 650 mW of power. The pulse repetition rate of the YDFL (EDLF) is 35 MHz (40 MHz).