Breathers introduce a new regime of mode locking into ultrafast lasers. The allfiber design is realized using a modefieldadaptor mfa to couple light onto the sesam. Pdf nonlinearity engineering of modelocked fiber lasers. Introduction for their outstanding characteristics, such as high gain, low noise, good thermal property, compactness, and ease in building and operation, femtosecond mode locked fiber lasers are finding more and more applications. Optical frequency combs generated by modelocked femtosecond fiber lasers are. Modelocked pulses in passive coherent beam combining. The stability of the proposed sa for modelocked operation was conducted for 60 min with results recorded at an interval of 2 min. We find new types of vector solitons with locked, switching and precessing states of polarization. Mxene ti 3 c 2 t x saturable absorber sa based on micro. However, their sensitivity to polarization limits their widespread application. Breathing dissipative solitons in modelocked fiber lasers.
Below that threshold, characteristic effects such as kelly sidebands can be seen. When operating in the anomalous dispersion regime, a laser emits pulses with shapes close to the hyperbolic secant profile of a conventional soliton. The practical advantages of allfiber laser configurations compactness, efficient heat dissipation, high beam quality, and easy alignmentmake them highly soughtafter. In order to generate ultrashort pulses in fiber lasers, passive mode locking has been widely reported based on several types of mechanism. Therefore, modelocked externalcavity diode lasers sometimes compete with modelocked fiber lasers in areas where monolithic laser diodes would not be suitable. With a single transverse mode, lasing occurs in longitudinal eigenmodes, which correspond to different patterns of the electromagnetic lasing field along the length of the fiber a and resonant frequencies b. Firstly, an environmentallystable and ultracompact sesam modelocked fiber laser is demonstrated. Wavelength and pulse duration tunable ultrafast fiber. Modelocked fiber lasers are widely used as sources of ultrashort optical pulses 1, 2, 3, 4. Stable subpicosecond soliton fiber laser passively modelocked by gigahertz acoustic resonance in photonic crystal fiber core m. Stable subpicosecond soliton fiber laser passively mode. In this letter, we demonstrate a hybrid scheme of erdoped mode locked fiber laser that incorporates the npe and semiconductor saturable absorber mirror sesam.
Modelocked thulium fiber laser with mos2 zhen tian, kan wu, lingchen kong et al. The modelocked fiber laser can be selfstarting and has a longtime stability, and is expected to become seed sources for highpower ultrashort pulse laser. Compared with the passively mode locked pulse laser with gdysa or npr technology alone, the output pulse width of hybrid passively mode locked fiber laser is reduced more than 50 fs. Ultrafast stretchedpulse fiber laser modelocked by. Our laser has successfully mode locked and stays mode locked untouched progressed autocorrelation technique for measuring ultrashort pulses conclusions. Modelocking is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, on the order of picoseconds 10.
Intracavity supercontinuum generation in a modelocked. Conceptual outline of modelocked multimode fiber lasers. Cw laser emits a continuous beam of light as long as medium is excited. This is particularly the case for short pulse durations, because these lead to a short. For this experiment, the polarization state was optimized and fixed at a constant orientation within the observation time. Using fast detection, we are able to observe the temporal and spectral evolutions of the breathers in real time. Modelocked fiber laser based on chalcogenide microwires. Pdf polarization attractors in harmonic modelocked. Switchable dualwavelength qswitched and modelocked. Investigations of the coupling between the core mode and cladding modes in a double clad ybdoped photonic crystal ber. Modelocked bulk lasers nearly never exhibit this effect. With the help of a diffraction grating, a carbon nanotube modelocked fiber laser tunable from 1860 nm to 2060 nm was reported, corresponding to a 200 nm tuni ng range 17. Modelocked fiber laser with mose 2 saturable absorber based on evanescent field to cite this article.
Dissipative soliton operation of an ytterbiumdoped fiber laser mode. Schematic representation of the master equation for an actively modelocked laser. Modelocking based on the mamyshev mechanism can be obtained easily. They exist in the laser cavity under the pump threshold of stationary mode locking. Nonlinear polarization evolutionbased passively modelocked fiber lasers with ultrafast and high peak power pulses are a powerful tool for engineering applications and scientific research. In the case of a soliton modelocked fiber laser, the quasisoliton pulses become unstable if the nonlinear effects per resonator round trip become too strong. Due to a nonreciprocal phase shift, the loop mirror can be operated in a compact and efficient reflection mode, offering the possibility to reach high repetition rates and easy implementation of tuning.
The basis of the technique is to induce a fixedphase relationship. Here, mxene ti 3 c 2 t x sa is used to achieve 36th harmonic mode. All polarizationmaintaining fiber laser architecture for. Osa intelligent programmable modelocked fiber laser.
Sub 20 attosecond timing jitter mode locked fiber lasers. J fiber laser at 976 nm article pdf available in optics letters 3619. In actively mode locked fiber lasers, as shown in fig. At the dualwavelength modelocked state, the fiber laser could achieve an output power of 2. A laser operated in this way is sometimes referred to as a femtosecond laser, for example in modern refractive surgery. The modelocked fiber laser was pumped at the maximum power of 177. The adaptive controller, based upon a multiparameter extremumseeking control algorithm, is capable of obtaining and maintaining highenergy, singlepulse states in a modelocked. Passively synchronized qswitched and modelocked dual.
Ultralow timing jitter optical pulse trains from mode. The pump power range associated with stable modelocking operation increases when the filter is inserted in the cavity. However, propagation of short pulses in optical fiber leads to. Previously, solitons, generated in fiber lasers modelocked by using the nonlinear polarization rotation npr technique 6. This laser achieves modelocking based on the mamyshev mechanism and realizes supercontinuum generation spanning from 30 nm to 2030 nm directly.
Since graphene can also be used to mode lock erbiumdoped fiber lasers, our result shows that. Russell1 1max planck institute for the science of light, guentherscharowskystrasse 1, 91058 erlangen, germany 2department of. Here, we present a simple and robust dualcomb system that employs a freerunning bidirectionally modelocked fiber. Chu city university of hong kong, hongkong abstract mode locked. The first allfiber modelocked laser used erdoped fiber edf as a gain medium, with an operating wavelength of 1550 nm 6,7. A fiber laser or fibre laser in british english is a laser in which the active gain medium is an optical fiber doped with rareearth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. We report on a novel architecture for robust modelocked femtosecond fiber lasers using a nonlinear optical loop mirror with all polarizationmaintaining fibers. In single wavelength operating configuration, the fiber laser can operate harmonic modelocking of 31 mhz repetition rate, which is two times. It is basically a standard nprbased, stretchedpulse fiber laser structure. This thesis is submitted to the faculty of science at the university of. In this letter, we report the first modelocked fiber laser based on a as2s3pmma chg microwire. This concept opens up new degrees of freedom in the design of modelocked fiber lasers. Modelocked thuliumdoped fiber laser with a narrow bandwidth and high pulse energy laser phys.
Period doubling eigenstates in a fiber laser modelocked. Generally, these types of laser cavities provide typically pulses larger. An allfiber supercontinuum laser source with a piece of highly nonlinear fiber inserted into a modelocked fiber laser is experimentally demonstrated. The modelocked fiber laser we investigated in this work is a nonlinear polarization rotation nprbased passively modelocked ybfiber laser, shown in fig. The fiber laser is passively modelocked with nonlinear polarization rotation npr 28, fig.
Our laser has successfully mode locked and stays modelocked untouched progressed autocorrelation technique for measuring ultrashort pulses conclusions. Wavelength tunable performance of the modelocked fiber laser with the filter. Modelocked lasers generate the highest peak power among lasers modelocked lasers provide one of the shortest events in nature modelocked lasers are one of the best frequency rulers modelocked lasers have the lowest timing jitter compared with most elec. Passively modelocked laser with the easy integration, high coupling efficiency and low loss, easy to adjust and maintain, high temperature stability, conversion efficiency and cost performance had attracted various attentions and exhibit numerous applications on space optical communication, sensing, lasermatter interaction, laser radar, biophotonics, remote. Schematic of fiber modelocked femtosecond laser with free space modelocking components. Modelocked fiber lasers with significant variability of generation. The polarization dependence of the latfg can induce npr effect in the laser cavity, and furthermore polarizationmode splitting enables polarization spectrum filtering.
In single wavelength operating configuration, the fiber laser can operate harmonic modelocking of 31 mhz repetition rate, which is two times of the fundamental repetition rate in our setup. Stability analysis of mode locked figureeight fiber laser. The output of a modelocked fiber laser depends strongly on the net dispersion of the laser cavity. Gase saturable absorber for modelocked erdoped fiber laser. The modelocking process is then described by the master equation tr. Pulsed laser emit light only in pulses from femtoseconds to second qswitched laserpulses from micro to nanosecond are produced. The modulation frequency has to be very precisely tuned to the resonator roundtrip time.
Introduction passively modelocked fiber lasers are attractive for many applications, such as optical communications 1, spectroscopy 2, and biomedical diagnostics 3, because of. Modelocking of fiber lasers using novel twodimensional. Probability density functions pdf for rmsbandwidth see fig. We report on a polarimetry of harmonic modelocked erbiumdoped fiber laser with carbon nanotubes saturable absorber. Large normal dispersion modelocked erbiumdoped fiber laser.
Stability analysis of mode locked figureeight fiber laser m. On the other hand, a monolithic setup with fundamental mode locking can be very compact, much cheaper to manufacture, and can exhibit very robust pulse emission. Allfiber modelocked ultrafast thuliumdoped fiber lasers at 2 m by qingqing wang b. Femtonanosecond switchable passively mode locked fiber laser. Passively modelocked fiber lasers, owing to their ultra. With their compact size, high efficiency, low maintenance, and ease of operation, advalue. Highenergy harmonic modelocked 2 m dissipative soliton fiber lasers nan yang, yulong tang and jianqiu xuhigh averagepeak power linearly polarized allfiber picosecond mopa seeded by modelocked noiselike pulses h l yu, p f ma, r m tao et al. Nanotubes, fiber laser, saturable absorber, ultrafast pulse generation 1. Pdf selfstarting ultrafast fiber lasers modelocked. The microwire has a length of 10 cm and exhibits a waveguide nonlinearity that is 104 times that of smf28. Theoretical and experimental developments carsten krogh nielsen department of physics and astronomy university of aarhus, denmark phd thesis december 2006. They are related to doped fiber amplifiers, which provide light amplification without lasing. Versatile modelocked operations in an erdoped fiber. Wider adoption of the technique has, however, been hindered by the need for complex and expensive ultrafast laser systems.
Nanotube modelocked, wavelength and pulsewidth tunable. The paper summarizes the recent achievements in the area of ultrafast fiber lasers modelocked with socalled low dimensional nanomaterials. B 28 014207 view the article online for updates and enhancements. Pdf fiber lasers are attractive with their simplicity, high powers and low cost. Pdf modelocked ytterbium fiber lasers lasse orsila. Two configuration erbiumdoped modelocked fiber lasers, single wavelength operation and multiwavelength operation, are study systematically. Fiber nonlinearities, such as stimulated raman scattering or.
Interesting facts about modelocked lasers modelocked lasers do not work 99. Modelocked pulses in passive coherent beam combining fiber laser arrays by chao zhang a dissertation submitted in partial ful. Paper modelocked fiber laser with mose 2 saturable. This study reveals that such a proposed filmtype ito sa has excellent nonlinear absorption. Thus, switchable dualwavelength qswitched and modelocked pulses have been achieved with. To address this, automatic modelocking immune to environmental disturbances is gaining attention. Laser physics spatiotemporal modelocking in multimode. Pdf modelocked nddoped fiber laser at 930 nm researchgate. The green glow is from twophoton pump upconversion in the erdoped gain fiber at 550nm. Allfiber coupled cavity fabryperot additive pulse modelocked laser.
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