Active fiber loop for synthesizing GHz bursts of equidistant ultrashort pulses

Abstract

We demonstrate a method to synthesize ultra-high repetition rate bursts of ultrashort laser pulses containing any number of pulses within a burst with identical pulse separation and adjustable amplitude. The key element to synthesize the GHz bursts of ultrashort laser pulses is an active fiber loop. The method was implemented in the fiber chirped pulse amplification system to obtain 72 nJ-energy bursts of 20 pulses with a 2.65 GHz intra-burst pulse repetition rate and a 500 kHz burst repetition rate. The dispersion compensation mechanism ensured a mean pulse duration of 570 fs within the bursts.

Ultra-Short Pulse Lasers for Microfabrication: A Review

“…The laser could be implemented in the burst mode to access GHz repetition rates and microjoule-level pulse energies without requiring kilo-watts of average power [33]. The 2.65 GHz repetition rate bursts of ultra-short laser pulses containing a desirable number of pulses within a burst with identical pulse separation and adjustable amplitude were demonstrated in an active fiber loop [34]. A burst mode all-fiber laser system operating at an intra-burst repetition rate of up to 1.2 GHz with pulse duration <500 fs and average power higher than 100 W [35].…”

Versatile ultrashort pulse laser tunable up to nanosecond range

“…The AFL is a versatile technology suitable to form GHz bursts of ultrashort laser pulses and to tune pulse duration even up to the nanosecond range. The main concept of GHz burst formation, its flexibility and advantages over other fiberbased techniques are presented in subsection 2.1 and our previous works more in detail [11][12][13]. Furthermore, in this work, we introduce patent-pending [14,15] modifications of the AFL technology which allow to tune the pulse duration from femtoseconds to nanoseconds and to shape the pulse spectrum (subsections 2.2 and 2.3).…”

“…In this work, we present a versatile technology based on the use of an active fiber loop (AFL) for GHz burst formation [11][12][13] and its modification which allowed to tune pulse duration from a few hundred femtoseconds to picoseconds and even up to the nanosecond pulse duration range. A patent-pending technology enabled new operation *t.bartulevicius@ekspla.com; phone +370 5 264 96 29 Fax; +370 5 264 18 09; ekspla.com regimes and a unique set of features in the industrial-grade 30 W-level average power femtosecond hybrid laser.…”

Control of the formation and amplification of pulse bursts in regenerative amplifiers

“…Due to nonlinear saturation effects of the gain medium, the amplification of pulse bursts typically results in a nonhomogeneous energy distribution of its individual pulses, which is why heuristic measurement-based homogenization strategies are suggested in the literature [8]. The desire to obtain pulse bursts with arbitrary burst envelope, that is, a desired energy distribution of the total burst energy into the individual pulses, stimulated the investigation of tailored amplifier systems [9] and experimental pre-shaping strategies [10,11], which typically rely on adjustable input filters. Finding suitable settings for these input filters such that the resulting output pulse burst exhibits a desired burst envelope can be quite tedious and has to be done for each desired burst envelope and operating point individually.…”