Multiple-Pulse Operation in Passively Mode-Locked Fibre Laser with Positive Dispersion Cavity

We report the observation of rectangular shape spectrum in passively mode-locked fibre laser with positive dispersion cavity. The spectrum is broad and flat, and 3dB bandwidth can be up to 17.61 nm. Multiple-pulse operation is observed in our laser system. The spectrum width, pulse energy, pulse width and peak power of the mode-locked laser output change with the appearance of multiple-pulse operation.

Passively Mode Locked Diode-End-Pumped Nd∶YAG Laser with In_(0.25)Ga_(0.75)As as Output Coupler

A novel InGaAs(LT-In 0.25Ga 0.75As) absorber grown by metal organic chemical vapor deposition at low temperature is presented.Using it as well as an output coupler,passive mode locking,which produces pulses as short as several hundred picoseconds for diode-end-pumped Nd∶YAG laser at 1.06μm,is realized.The pulse frequency is 150MHz.

Application of ABCD Formalism in Theoretical and Experimental Analysis of Actively Modelocked Fiber Laser

Time domain ABCD matrix formalism is a useful model for analyzing the characteristics of actively modelocked fiber laser. Based on this model and given more consideration on the influences of optical fiber dispersion and optical fiber nonlinearity, the laser characteristic of actively modelocked fiber laser is analyzed, and the comparision of the theoretical analysis results with experimental ones is given.

Highly stable and repeatable femtosecond soliton pulse generation from saturable absorbers based on twodimensional Cu3-xP nanocrystals

Heavily doped colloidal plasmonic nanocrystals have attracted great attention because of their lower and adjustable free carrier densities and tunable localized surface plasmonic resonance bands in the spectral range from near-infra to mid-infra wavelengths.With its plasmon-enhanced optical nonlinearity,this new family of plasmonic materials shows a huge potential for nonlinear optical applications,such as ultrafast switching,nonlinear sensing,and pulse laser generation.Cu3-xP nanocrystals were previously shown to have a strong saturable absorption at the plasmonic resonance,which enabled high-energy Q-switched fiber lasers with 6.1μs pulse duration.This work demonstrates that both high-quality mode-locked and Q-switched pulses at 1560 nm can be generated by evanescently incorporating two-dimensional(2D)Cu3-xP nanocrystals onto a D-shaped optical fiber as an effective saturable absorber.The 3 dB bandwidth of the mode-locking optical spectrum is as broad as 7.3 nm,and the corresponding pulse duration can reach 423 fs.The repetition rate of the Q-switching pulses is higher than 80 kHz.Moreover,the largest pulse energy is more than 120μJ.Note that laser characteristics are highly stable and repeatable based on the results of over 20 devices.This work may trigger further investigations on heavily doped plasmonic 2D nanocrystals as a next-generation,inexpensive,and solution-processed element for fascinating photonics and optoelectronics applications.

Passively Q-switched and femtosecond modelocked erbium-doped fiber laser based on a 2D palladium disulfide(PdS2) saturable absorber

Stable Q-switched and mode-locked erbium-doped fiber lasers(EDFLs)are first demonstrated by using the novel layered palladium disulfide(PdS2),a new member of group 10 transition metal dichalcogenides(TMDs)-based saturable absorbers(SAs).Self-started Q-switched operation at 1567 nm was achieved with a threshold pump power of 50.6 mW.The modulation ranges of pulse duration and repetition rate were characterized as 12.6-4.5μs and 17.2-26.0 kHz,respectively.Meanwhile,a mode-locked EDFL was also obtained with a pump power threshold of 106.4 mW.The achieved pulse duration is 803 fs,corresponding to a center wavelength of 1565.8 nm and4.48 nm 3 dB bandwidth.To the best of our knowledge,the achieved pulse duration of the mode-locked EDFL in this work is the narrowest compared with all other group 10 TMD SA-based lasers.

Recent advances in ultrafast semiconductor disk lasers

The performance of ultrafast semiconductor disk lasers has rapidly advanced in recent decades.The strong interest from industry for inexpensive,compact,and reliable ultrafast laser sources in the picosecond and femtosecond domains has driven this technology toward commercial products.Frequency metrology and biomedical applications would benefit from sub-200-femtosecond pulse durations with peak powers in the kilowatt range.The aim of this review is to briefly describe the market potential and give an overview of the current status of mode-locked semiconductor disk lasers.Particular focus is placed on the ongoing efforts to achieve shorter pulses with higher peak powers.

Graphene-based saturable absorber and mode-locked laser behaviors under gamma-ray radiation

We investigate optical and electrical behaviors of a graphene saturable absorber (SA) and mode-locking performance of a graphene-SA-based mode-locked Er fiber laser in gamma-ray radiation. When irradiated up to 4.8 kGy at ~ 100 Gy/hr dose rate, the overall nonlinear transmittance in transverse electric mode was increased, while maintaining modulation depth to >10%. The corresponding polarization.dependent loss was reduced at a 1.2-dB/kGy rate. In the electrical properties, the charge carrier mobility was reduced, and the Dirac voltage shift was increased to positive under gamma-ray radiation. The radiation-induced optical and electrical changes turned out to be almost recovered after a few days. In addition, we confirmed that the graphene-SA-based laser showed stable CW mode-locking operation while the inserted graphene SA was irradiated for 2-kGy at a 45-Gy/hr dose rate, which corresponds to >40 years of operation in low Earth orbit satellites.To the best of our knowledge, this is the first evaluation of graphene SAs and graphene-SA-based mode-locked lasers in gamma-ray radiation, and the measured results confirm the high potential of graphene SAs and graphene-SA-based lasers in various outer-space environments as well as other radiation environments, including particle accelerators and radiationbased medical instruments.

Hybrid-type passively and actively modelocked fiber laser with a DI-NOLM

We present a 10-GHz hybrid actively and passively mode-locked fiber ring laser with a dispersion im-balanced nonlinear loop mirror (DI-NOLM), whose nonlinear switching characteristic can make the laser operate at additive pulse modelocking (APM) mode or additive pulse limiting (APL) mode. When the laser operated at APM, 5.45 ps of transform-limited pulse series were obtained. When the laser was biased at APL region, supermode noise was suppressed and the laser output was more stable.