Burst Amplification Research Articles

Frequency-mode-stable regenerative amplification at terahertz burst rates

Generation of high-fidelity amplified pulse bursts with a regular interpulse interval yields, in the spectral domain, an equidistant pattern of narrowband spectral modes, similar to frequency combs produced by cw mode-locked lasers but with greatly increased pulse energy. Despite their great potential for nonlinear spectroscopy, material processing, etc., such long frequency-stable bursts are difficult to generate and amplify because of prominent temporal intensity modulation even after strong dispersive pulse stretching. This study presents a burst generation method based on a master-oscillator regenerative-amplifier system that allows for chirped-pulse amplification (CPA) with high scalability in pulse number. A gradual smoothing of temporal intensity profiles at an increasing number of pulses is discovered, demonstrating an unexpected recovery of the CPA performance at terahertz intraburst repetition rates. In consequence, a self-referenced stable burst spectral peak structure with megahertz peak width is generated without risk of amplifier damage caused by interference of chirped pulses. This result eliminates limitations in burst amplification and paves the way for advancements in ultrashort-pulse burst technology, particularly for its use in nonlinear optical applications.

Methods and Applications for Amplified Bursts of Picosecond-Spaced Ultrashort Pulses

Generating packages of picosecond-spaced ultrashort pulses yields various advantages in their application in nonlinear spectroscopy, micromachining, and plasma generation. We outline methods of burst amplification, with a focus on recent advancements in the generation and application of amplified pulse bursts.

Programmable generation of terahertz bursts in chirped-pulse laser amplification

Amplified bursts of laser pulses are sought for various machining, deposition, spectroscopic, and strong-field applications. Standard frequency- and time-domain techniques for pulse division become inadequate when intraburst repetition rates reach the terahertz (THz) range as a consequence of inaccessible spectral resolution, requirement for interferometric stability, and collapse of the chirped-pulse amplification (CPA) concept due to the loss of usable bandwidth needed for safe temporal stretching. Avoiding the burst amplification challenge and resorting to lossy post-division of an isolated laser pulse after CPA leaves the limitations of frequency- and time-domain techniques unsolved. In this Letter, we demonstrate an approach that successfully combines amplitude and phase shaping of THz bursts, formed using the Vernier effect, with active stabilization of spectral modes and efficient energy extraction from a CPA regenerative amplifier. As proof of concept, the amplified bursts of femtosecond near-infrared pulses are down-converted into tunable THz-frequency pulses via optical rectification.

Stabilization of burst laser pulse storage in an optical enhancement cavity using a counter propagating mode.

We describe the stabilization technique of an optical enhancement cavity using a counter propagating mode. The burst amplification of the injection laser in the main path induces a drastic change in the laser intensity and disturbs the stabilization of the enhancement cavity. We have used a counter propagating mode to achieve a 4% intensity jitter and 0.6 mJ pulse storage inside the cavity at the maximum of the burst region. Our results indicate that the counter propagating mode has the same resonant condition as the main mode and thus becomes useful for stabilizing the enhancement cavity. We also determined that the burst amplification brought about no decrease in the enhancement factor in the cavity due to the degradation of laser quality.

All-optical integrated support for multicast and burst amplif ication in transparent optical network

A novel scalable and integrated design that supports optical multicast and burst amplification is proposed and demonstrated experimentally. The powers of incoming signals can be tuned to optimize the results of burst amplification and replication. Experimental results also show that erbium-doped optical Fiber amplication (EDFA) transients can be suppressed to an equally low level regardless of the burst parameters. Extended structure designs are further proposed to satisfy the need of mass replication of multicast signals.

Unified support for integrated all-optical multicast and burst amplification in transparent optical network

To better support transparent optical network, we present a novel scalable structure design based on multi-wavelength conversion (MWC) for integrated optical multicast and burst amplification in this paper. We also propose a corresponding wavelength assignment algorithm to minimize the cost of wavelength conversions in the multicast tree. MWC-based multicast strategy makes it possible to generate data copies through less processes and simplifies the wavelength assignment problem. Meanwhile, the generated data copies are used as complementary signals to compensate the power variations of original signal for Erbium-doped fiber amplifiers transient suppression. Experiments are conducted to demonstrate the performance of both burst amplification and multicast data generation in one MWC process. Simulation results are given for our new wavelength assignment algorithm, and advantages are shown over greedy algorithms.

Nonlinear dynamics induced by burst amplification in optically gain-stabilized erbium-doped amplifiers

Optical burst amplification in a gain-stabilized amplifier may generate complex gain dynamics with nonlinear behavior. This phenomenon is thoroughly investigated by using a theoretical model and dedicated experiments. Design guidelines for optimized devices avoiding optical burst transmission impairments are proposed.

The role of release bursts in the perception of [s]-stop clusters.

The role of the release burst as a cue to the perception of stop consonants following [s] was investigated in a series of studies. Experiment 1 demonstrated that silent closure duration and burst duration can be traded as cues for the "say"-"stay" distinction. Experiment 2 revealed a similar trading relation between closure duration and burst amplitude. Experiments 3 and 4 suggested, perhaps surprisingly, that absolute, not relative, burst amplitude is important. Experiment 5 demonstrated that listener's sensitivity to bursts in a labeling task is at least equal to their sensitivity in a burst detection task. Experiments 6 and 7 replicated the trading relation between closure duration and burst amplitude for labial stops in the "slit"-"split" and "slash"-"splash" distinctions, although burst amplification, in contrast to attenuation, had no effect. All experiments revealed that listeners are remarkably sensitive to the presence of even very weak release bursts.