Showing papers on "Fiber laser published in 2015"
TL;DR: The saturable absorption property of the fabricated BP-SAs at the telecommunication band is characterized and shows that BP could also be developed as an effective SA for pulsed fiber or solid-state lasers.
Abstract: Black phosphorus (BP), an emerging narrow direct band-gap two-dimensional (2D) layered material that can fill the gap between the semi-metallic graphene and the wide-bandgap transition metal dichalcogenides (TMDs), had been experimentally found to exhibit the saturation of optical absorption if under strong light illumination. By taking advantage of this saturable absorption property, we could fabricate a new type of optical saturable absorber (SA) based on mechanically exfoliated BPs, and further demonstrate the applications for ultra-fast laser photonics. Based on the balanced synchronous twin-detector measurement method, we have characterized the saturable absorption property of the fabricated BP-SAs at the telecommunication band. By incorporating the BP-based SAs device into the all-fiber Erbium-doped fiber laser cavities, we are able to obtain either the passive Q-switching (with maximum pulse energy of 94.3 nJ) or the passive mode-locking operation (with pulse duration down to 946 fs). Our results show that BP could also be developed as an effective SA for pulsed fiber or solid-state lasers.
837 citations
TL;DR: This work may constitute the first example of MoS2-enabled wave-guiding photonic device, and potentially give some new insights into two-dimensional layered materials related photonics.
Abstract: By coupling few-layer Molybdenum Disulfide (MoS2) with fiber-taper evanescent light field, a new type of MoS2 based nonlinear optical modulating element had been successfully fabricated as a two-dimensional layered saturable absorber with strong light-matter interaction. This MoS2-taper-fiber device is not only capable of passively mode-locking an all-normal-dispersion ytterbium-doped fiber laser and enduring high power laser excitation (up to 1 W), but also functions as a polarization sensitive optical modulating component (that is, different polarized light can induce different nonlinear optical response). Thanks to the combined advantages from the strong nonlinear optical response in MoS2 together with the sufficiently-long-range interaction between light and MoS2, this device allows for the generation of high power stable dissipative solitons at 1042.6 nm with pulse duration of 656 ps and a repetition rate of 6.74 MHz at a pump power of 210 mW. Our work may also constitute the first example of MoS2-enabled wave-guiding photonic device, and potential y give some new insights into two-dimensional layered materials related photonics.
428 citations
TL;DR: It is found that MoSe(2) exhibits highest modulation depth with similar preparation process among four saturable absorbers, which demonstrates the feasibility of TMDs to Q-switch fiber laser effectively.
Abstract: In this paper, we report 4 different saturable absorbers based on 4 transition metal dichalcogenides (MoS2, MoSe2, WS2, WSe2) and utilize them to Q-switch a ring-cavity fiber laser with identical cavity configuration. It is found that MoSe2 exhibits highest modulation depth with similar preparation process among four saturable absorbers. Q-switching operation performance is compared from the aspects of RF spectrum, optical spectrum, repetition rate and pulse duration. WS2 Q-switched fiber laser generates the most stable pulse trains compared to other 3 fiber lasers. These results demonstrate the feasibility of TMDs to Q-switch fiber laser effectively and provide a meaningful reference for further research in nonlinear fiber optics with these TMDs materials.
414 citations
TL;DR: It is demonstrated for the first time that WS2 nanosheets exhibit ultrafast nonlinear saturable absorption property and high optical damage threshold, indicating that few-layer WS2 is a promising high-power flexible saturable absorber for ultrafast optics.
Abstract: Graphene-like two dimensional materials, such as WS2 and MoS2, are highly anisotropic layered compounds that have attracted growing interest from basic research to practical applications. Similar with MoS2, few-layer WS2 has remarkable physical properties. Here, we demonstrate for the first time that WS2 nanosheets exhibit ultrafast nonlinear saturable absorption property and high optical damage threshold. Soliton mode-locking operations are achieved separately in an erbium-doped fiber laser using two types of WS2-based saturable absorbers, one of which is fabricated by depositing WS2 nanosheets on a D-shaped fiber, while the other is synthesized by mixing WS2 solution with polyvinyl alcohol, and then evaporating them on a substrate. At the maximum pump power of 600 mW, two saturable absorbers can work stably at mode-locking state without damage, indicating that few-layer WS2 is a promising high-power flexible saturable absorber for ultrafast optics. Numerous applications may benefit from the ultrafast nonlinear features of WS2 nanosheets, such as high-power pulsed laser, materials processing, and frequency comb spectroscopy.
409 citations
TL;DR: The results not only demonstrate that black phosphorus might be another promising SA material for ultrafast photonics, but also provide a practical solution to solve the optical damage problem of black phosphorus by assembling with waveguide structures such as microfiber.
Abstract: Few-layer black phosphorus (BP), as the most alluring graphene analogue owing to its similar structure as graphene and thickness dependent direct band-gap, has now triggered a new wave of research on two-dimensional (2D) materials based photonics and optoelectronics However, a major obstacle of practical applications for few-layer BPs comes from their instabilities of laser-induced optical damage Herein, we demonstrate that, few-layer BPs, fabricated through the liquid exfoliation approach, can be developed as a new and practical saturable absorber (SA) by depositing few-layer BPs with microfiber The saturable absorption property of few-layer BPs had been verified through an open-aperture z-scan measurement at the telecommunication band and the microfiber-based BP device had been found to show a saturable average power of ~45 mW and a modulation depth of 109%, which is further confirmed through a balanced twin detection measurement By further integrating this optical SA device into an erbium-doped fiber laser, it was found that it can deliver the mode-locked pulse with duration down to 940 fs with central wavelength tunable from 1532 nm to 1570 nm The prevention of BP from oxidation through the 'lateral interaction scheme' owing to this microfiber-based few-layer BP SA device might partially mitigate the optical damage problem of BP Our results not only demonstrate that black phosphorus might be another promising SA material for ultrafast photonics, but also provide a practical solution to solve the optical damage problem of black phosphorus by assembling with waveguide structures such as microfiber
347 citations
TL;DR: In this paper, a microfiber-based few-layer black phosphorus (BP) SA device is proposed to solve the optical damage problem of black phosphorus by assembling with waveguide structures such as micro-fiber, which can deliver the mode-locked pulse with duration down to 940 fs with central wavelength tunable from 1532 nm to 1570 nm.
Abstract: Few-layer black phosphorus (BP), as the most alluring graphene analogue owing to its similar structure as graphene and thickness dependent direct band-gap, has now triggered a new wave of research on two-dimensional (2D) materials based photonics and optoelectronics. However, a major obstacle of practical applications for few-layer BPs comes from their instabilities of laser-induced optical damage. Herein, we demonstrate that, few-layer BPs, which was fabricated through the liquid exfoliation approach, can be developed as a new and practical saturable absorber (SA) by depositing few-layer BPs with microfiber. The saturable absorption property of few-layer BPs had been verified through an open-aperture z-scan measurement at the telecommunication band. The microfiber-based BP device had been found to show a saturable average power of ~4.5 mW and a modulation depth of 10.9%, which is further confirmed through a balanced twin detection measurement. By integrating this optical SA device into an erbium-doped fiber laser, it was found that it can deliver the mode-locked pulse with duration down to 940 fs with central wavelength tunable from 1532 nm to 1570 nm. The prevention of BP from oxidation through the "lateral interaction scheme" owing to this microfiber-based few-layer BP SA device might partially mitigate the optical damage problem of BP. Our results not only demonstrate that black phosphorus might be another promising SA material for ultrafast photonics, but also provide a practical solution to solve the optical damage problem of black phosphorus by assembling with waveguide structures such as microfiber.
329 citations
20 Jan 2015
TL;DR: In this article, the authors identify clear explosion signatures in measurements of shot-to-shot spectra of a Yb-doped mode-locked fiber laser that is operating in a transition regime between stable and noise-like emission.
Abstract: Soliton explosions are among the most exotic dissipative phenomena studied in mode-locked lasers. In this regime, a dissipative soliton circulating in the laser cavity experiences an abrupt structural collapse, but within a few roundtrips returns to its original quasi-stable state. In this Letter, we report on the first observation, to the best of our knowledge, of such events in a fiber laser. Specifically, we identify clear explosion signatures in measurements of shot-to-shot spectra of a Yb-doped mode-locked fiber laser that is operating in a transition regime between stable and noise-like emission. The comparatively long, all-normal-dispersion cavity used in our experiments also permits direct time-domain measurements, and we show that the explosions manifest themselves as abrupt temporal shifts in the output pulse train. Our experimental results are in good agreement with realistic numerical simulations based on an iterative cavity map.
328 citations
TL;DR: These findings suggest that few-layer WS2 nanosheets embedded in PVA thin film are promising nonlinear optical materials for ultrafast photonic applications as a mode locker or Q-switcher.
Abstract: Two-dimensional (2D) nanomaterials, especially the transition metal sulfide semiconductors, have drawn great interests due to their potential applications in viable photonic and optoelectronic devices. In this work, 2D tungsten disulfide (WS2) based saturable absorber (SA) for ultrafast photonic applications was demonstrated. WS2 nanosheets were prepared using liquid-phase exfoliation method and embedded in polyvinyl alcohol (PVA) thin film for the practical usage. Saturable absorption was discovered in the WS2-PVA SA at the telecommunication wavelength near 1550 nm. By incorporating WS2-PVA SA into a fiber laser cavity, both stable mode locking operation and Q-switching operation were achieved. In the mode locking operation, the laser obtained femtosecond output pulse width and high spectral purity in the radio frequency spectrum. In the Q-switching operation, the laser had tunable repetition rate and output pulse energy of a few tens of nano joule. Our findings suggest that few-layer WS2 nanosheets embedded in PVA thin film are promising nonlinear optical materials for ultrafast photonic applications as a mode locker or Q-switcher.
326 citations
TL;DR: It is experimentally shown that BP exhibits saturable absorption in the 2 μm wavelength range and supports ultrashort pulse generation and might be considered as a universal broadband saturable absorber that could successfully compete with graphene or other low-dimension nanomaterials.
Abstract: We report, for the first time to our knowledge, the usage of black phosphorus (BP) as a saturable absorber for the mode locking of a thulium-doped fiber laser. We have experimentally shown that BP exhibits saturable absorption in the 2 μm wavelength range and supports ultrashort pulse generation. The saturable absorber was based on mechanically exfoliated BP deposited on a fiber connector tip. The laser was capable of generating 739 fs pulses centered at 1910 nm. Our results show that BP might be considered as a universal broadband saturable absorber that could successfully compete with graphene or other low-dimension nanomaterials.
318 citations
TL;DR: In this article, the authors present a guided tour of laser feedback interferometry, from its origin and early development through its implementation to a slew of sensing applications, including displacement, distance, velocity, flow, refractive index, and laser linewidth measurement.
Abstract: This tutorial presents a guided tour of laser feedback interferometry, from its origin and early development through its implementation to a slew of sensing applications, including displacement, distance, velocity, flow, refractive index, and laser linewidth measurement Along the way, we provide a step-by-step derivation of the basic rate equations for a laser experiencing optical feedback starting from the standard Lang and Kobayashi model and detail their subsequent reduction in steady state to the excess-phase equation We construct a simple framework for interferometric sensing applications built around the laser under optical feedback and illustrate how this results in a series of straightforward models for many signals arising in laser feedback interferometry Finally, we indicate promising directions for future work that harnesses the self-mixing effect for sensing applications
302 citations
TL;DR: In this article, the authors demonstrate that black phosphorus can serve as a broadband saturable absorber and can be used for ultrashort optical pulse generation with performances similar or even better than currently used graphene or carbon nanotubes.
Abstract: Low-dimensional materials, due to their unique and versatile properties, are very interesting for numerous applications in electronics and optoelectronics. Recently rediscovered black phosphorus, with a graphite-like layered structure, can be effectively exfoliated up to the single atomic layer called phosphorene. Contrary to graphene, it possesses a direct band gap controllable by the number of stacked atomic layers. For those reasons, black phosphorus is now intensively investigated and can complement or replace graphene in various photonics and electronics applications. Here, we demonstrate that black phosphorus can serve as a broadband saturable absorber and can be used for ultrashort optical pulse generation. The mechanically exfoliated ∼300 nm thick layers of black phosphorus were transferred onto the fiber core, and under pulsed excitation at 1560 nm wavelength, its transmission increases by 4.6%. We have demonstrated that the saturable absorption of black phosphorus is polarization sensitive. The fabricated device was used to mode-lock an Er-doped fiber laser. The generated optical solitons with the 10.2 nm bandwidth and 272 fs duration were centered at 1550 nm. The obtained results unambiguously show that black phosphorus can be effectively used for ultrashort pulse generation with performances similar or even better than currently used graphene or carbon nanotubes. This application of black phosphorus proves its great potential to future practical use in photonics.
TL;DR: The results underscore the relatively large optical nonlinearity of BP with unique polarization and thickness dependence, and its potential for polarized optical pulse generation, paving the way to BP based nonlinear and ultrafast photonic applications (e.g., ultrafast all-optical polarization switches/modulators, frequency converters etc.).
Abstract: Black phosphorus (BP) has recently been rediscovered as a new and interesting two-dimensional material due to its unique electronic and optical properties. Here, we study the linear and nonlinear optical properties of BP flakes. We observe that both the linear and nonlinear optical properties are anisotropic and can be tuned by the film thickness in BP, completely different from other typical two-dimensional layered materials (e.g., graphene and the most studied transition metal dichalcogenides). We then use the nonlinear optical properties of BP for ultrafast (pulse duration down to ~786 fs in mode-locking) and large-energy (pulse energy up to >18 nJ in Q-switching) pulse generation in fiber lasers at the near-infrared telecommunication band ~1.5 μm. We observe that the output of our BP based pulsed lasers is linearly polarized (with a degree-of-polarization ~98% in mode-locking, >99% in Q-switching, respectively) due to the anisotropic optical property of BP. Our results underscore the relatively large optical nonlinearity of BP with unique polarization and thickness dependence, and its potential for polarized optical pulse generation, paving the way to BP based nonlinear and ultrafast photonic applications (e.g., ultrafast all-optical polarization switches/modulators, frequency converters etc.).
TL;DR: To the best of the knowledge, this is the first time that black phosphorus can realize Q-switching of 2.8-μm fiber laser and the research results show thatblack phosphorus is a promising saturable absorber for mid-infrared pulsed lasers.
Abstract: Black phosphorus, a newly emerged two-dimensional material, has attracted wide attention as novel photonic material. Here, multilayer black phosphorus is successfully fabricated by liquid phase exfoliation method. By employing black phosphorus as saturable absorber, we demonstrate a passively Q-switched Er-doped ZBLAN fiber laser at the wavelength of 2.8 μm. The modulation depth and saturation fluence of the black phosphorus saturable absorber are measured to be 15% and 9 μJ/cm(2), respectively. The Q-switched fiber laser delivers a maximum average power of 485 mW with corresponding pulse energy of 7.7 μJ and pulse width of 1.18 μs at repetition rate of 63 kHz. To the best of our knowledge, this is the first time to demonstrate that black phosphorus can realize Q-switching of 2.8-μm fiber laser. Our research results show that black phosphorus is a promising saturable absorber for mid-infrared pulsed lasers.
TL;DR: In this paper, a few-layer molybdenum disulfide (MoS2)-polymer composite by liquid phase exfoliation of chemically pristine MoS2 crystals is used to demonstrate a wideband tunable, ultrafast mode-locked fiber laser.
Abstract: We fabricate a free-standing few-layer molybdenum disulfide (MoS2)-polymer composite by liquid phase exfoliation of chemically pristine MoS2 crystals and use this to demonstrate a wideband tunable, ultrafast mode-locked fiber laser. Stable, picosecond pulses, tunable from 1,535 nm to 1,565 nm, are generated, corresponding to photon energies below the MoS2 material bandgap. These results contribute to the growing body of work studying the nonlinear optical properties of transition metal dichalcogenides that present new opportunities for ultrafast photonic applications.
TL;DR: In this paper, a free-standing molybdenum diselenide (MoSe2) saturable absorber was fabricated by embedding liquid-phase exfoliated few-layer MoSe2 flakes into a polymer film, which is used to Q-switch fiber lasers based on ytterbium (Yb), erbium(Er) and thulium (Tm) gain fiber, producing trains of microsecond-duration pulses with kilohertz repetition rates at 1060 nm, 1566 nm and 1924 nm, respectively.
Abstract: We fabricate a free-standing molybdenum diselenide (MoSe2) saturable absorber by embedding liquid-phase exfoliated few-layer MoSe2 flakes into a polymer film. The MoSe2-polymer composite is used to Q-switch fiber lasers based on ytterbium (Yb), erbium (Er) and thulium (Tm) gain fiber, producing trains of microsecond-duration pulses with kilohertz repetition rates at 1060 nm, 1566 nm and 1924 nm, respectively. Such operating wavelengths correspond to sub-bandgap saturable absorption in MoSe2, which is explained in the context of edge-states, building upon studies of other semiconducting transition metal dichalcogenide (TMD)-based saturable absorbers. Our work adds few-layer MoSe2 to the growing catalog of TMDs with remarkable optical properties, which offer new opportunities for photonic devices.
TL;DR: An overview of recent advances in the random fiber laser field, including high-power and high-efficiency generation, spectral and statistical properties of random fiber lasers, nonlinear kinetic theory of such systems, and emerging applications in telecommunications and distributed sensing are provided.
Abstract: Random fiber lasers blend together attractive features of traditional random lasers, such as low cost and simplicity of fabrication, with high-performance characteristics of conventional fiber lasers, such as good directionality and high efficiency. Low coherence of random lasers is important for speckle-free imaging applications. The random fiber laser with distributed feedback proposed in 2010 led to a quickly developing class of light sources that utilize inherent optical fiber disorder in the form of the Rayleigh scattering and distributed Raman gain. The random fiber laser is an interesting and practically important example of a photonic device based on exploitation of optical medium disorder. We provide an overview of recent advances in this field, including high-power and high-efficiency generation, spectral and statistical properties of random fiber lasers, nonlinear kinetic theory of such systems, and emerging applications in telecommunications and distributed sensing.
TL;DR: In this article, the authors describe the physics that explains the optical properties of disordered nanostructures and scattering used to develop the random lasers, particularly discussing the role of modes in random lasers.
TL;DR: This work fabricates a free-standing molybdenum diselenide (MoSe2) saturable absorber by embedding liquid-phase exfoliated few-layer MoSe2 flakes into a polymer film that is used to Q-switch fiber lasers based on ytterbium, erbium and thulium gain fiber, producing trains of microsecond-duration pulses.
Abstract: We fabricate a free-standing molybdenum diselenide (MoSe2) saturable absorber by embedding liquid-phase exfoliated few-layer MoSe2 flakes into a polymer film. The MoSe2-polymer composite is used to Q-switch fiber lasers based on ytterbium (Yb), erbium (Er) and thulium (Tm) gain fiber, producing trains of microsecond-duration pulses with kilohertz repetition rates at 1060 nm, 1566 nm and 1924 nm, respectively. Such operating wavelengths correspond to sub-bandgap saturable absorption in MoSe2, which is explained in the context of edge-states, building upon studies of other semiconducting transition metal dichalcogenide (TMD)-based saturable absorbers. Our work adds few-layer MoSe2 to the growing catalog of TMDs with remarkable optical properties, which offer new opportunities for photonic devices.
TL;DR: In this article, the linear and nonlinear optical properties of black phosphorus thin films are investigated and shown to be controllable by the thickness of the thin film, indicating that the properties can be tuned by the film thickness.
Abstract: Black phosphorus has been recently rediscovered as a new and interesting
two-dimensional material due to its unique electronic and optical properties.
Here, we study the linear and nonlinear optical properties of black phosphorus
thin films, indicating that both linear and nonlinear optical properties are
anisotropic and can be tuned by the film thickness. Then we employ the
nonlinear optical property of black phosphorus for ultrafast (pulse duration
down to ~786 fs in mode-locking) and large-energy (pulse energy up to >18 nJ in
Q-switching) pulse generation in fiber lasers at the near-infrared
telecommunication band ~1.5 {\mu}m. Our results underscore relatively large
optical nonlinearity in black phosphorus and its prospective for ultrafast
pulse generation, paving the way to black phosphorus based nonlinear and
ultrafast photonics applications (e.g., ultrafast all-optical
switches/modulators, frequency converters etc.).
TL;DR: In this paper, the use of solution exfoliated black phosphorus (BP) as a saturable absorber for high energy pulse generation in fiber laser is demonstrated and two fabrication approaches are demonstrated to produce BP-polymer composite films which are further incorporated into fiber laser cavity as nonlinear media.
Abstract: Black phosphorus (BP) is a very promising material for telecommunication due to its direct bandgap and strong resonant absorption in near-infrared wavelength range. However, ultrafast nonlinear photonic applications relying on the ultrafast photocarrier dynamics as well as optical nonlinearity in black phosphorus remain unexplored. In this work, nonlinear optical properties of solution exfoliated BP are investigated and the usage of BP as a new saturable absorber for high energy pulse generation in fiber laser is demonstrated. In order to avoid the oxidization and degradation, BP is encapsulated by polymer matrix which is optically transparent in the spectrum range of interest to form a composite. Two fabrication approaches are demonstrated to produce BP-polymer composite films which are further incorporated into fiber laser cavity as nonlinear media. BP shows very fast carrier dynamics and BP-polymer composite has a modulation depth of 10.6%. A highly stable Q-switched pulse generation is achieved and the single pulse energy of 194 nJ is demonstrated. The ease of handling of such black phosphorus-polymer composite thin films affords new opportunities for wider applications such as optical sensing, signal processing, and light modulation.
TL;DR: In this article, both nonlinear saturable absorption and two-photon absorption (TPA) of few-layer molybdenum diselenide (MoSe2) were observed at 1.56μm wavelength and further applied to mode-locked ultrafast fiber laser for the first time to the knowledge.
Abstract: In this paper, both nonlinear saturable absorption and two-photon absorption (TPA) of few-layer molybdenum diselenide (MoSe2) were observed at 1.56 μm wavelength and further applied to mode-locked ultrafast fiber laser for the first time to our knowledge. Few-layer MoSe2 nanosheets were prepared by liquid-phase exfoliation method and characterized by x ray diffractometer, Raman spectroscopy, and atomic force microscopy. The obtained few-layer MoSe2 dispersion is further composited with a polymer material for convenient fabrication of MoSe2 thin films. Then, we investigated the nonlinear optical (NLO) absorption property of the few-layer MoSe2 film using a balanced twin-detector measurement technique. Both the saturable absorption and TPA effects of the few-layer MoSe2 film were found by increasing the input optical intensity. The saturable absorption shows a modulation depth of 0.63% and a low nonsaturable loss of ∼3.5%, corresponding to the relative modulation depth of 18%. The TPA effect occurred when the input optical intensity exceeds ∼260 MW/cm2. Furthermore, we experimentally exploit the saturable absorption of few-layer MoSe2 film to mode lock an all-fiber erbium-doped fiber laser. Stable soliton mode locking at 1558 nm center wavelength is achieved with pulse duration of 1.45 ps. It was also observed that the TPA process suppresses the mode-locking operation in the case of higher optical intensity. Our results indicate that layered MoSe2, as another two-dimensional nanomaterial, can provide excellent NLO properties (e.g., saturable absorption and TPA) for potential applications in ultrashort pulse generation and optical limiting.
TL;DR: In this article, a novel method is proposed to enable the control on the self-amplitude modulation (SAM) of TI by adjusting its dopant type, which results in more capacity for excited carriers than the n-type TI.
Abstract: Mechanically triturated n- and p-type Bi2Te3 nanoparticles, the nanoscale topological insulators (TIs), are employed as nonlinear saturable absorbers to passively mode-lock the erbium-doped fiber lasers (EDFLs) for sub-400 fs pulse generations. A novel method is proposed to enable the control on the self-amplitude modulation (SAM) of TI by adjusting its dopant type. The dopant type of TI only shifts the Fermi level without changing its energy bandgap, that the n- and p-type Bi2Te3 nanoparticles have shown the broadband saturable absorption at 800 and 1570 nm. In addition, both the complicated pulse shortening procedure and the competition between hybrid mode-locking mechanisms in the Bi2Te3 nanoparticle mode-locked EDFL system have been elucidated. The p-type Bi2Te3 with its lower effective Fermi level results in more capacity for excited carriers than the n-type Bi2Te3, which shortens the pulse width by enlarging the SAM depth. However, the strong self-phase modulation occurs with reduced linear loss and...
TL;DR: In this paper, a passively Q-switched Er-doped ZBLAN fiber laser at the wavelength of 2.8 µm was demonstrated, achieving a maximum average power of 485 mW with corresponding pulse energy of 7.7 µm and pulse width of 1.18 µm at repetition rate of 63 kHz.
Abstract: Black phosphorus, a newly emerged two-dimensional material, has attracted wide attention as novel photonic material. Here, multi-layer black phosphorus is successfully fabricated by liquid phase exfoliation method. By employing black phosphorus as saturable absorber, we demonstrate a passively Q-switched Er-doped ZBLAN fiber laser at the wavelength of 2.8 {\mu}m. The modulation depth and saturation fluence of the black phosphorus saturable absorber are measured to be 15% and 9 {\mu}J/cm2, respectively. The Q-switched fiber laser delivers a maximum average power of 485 mW with corresponding pulse energy of 7.7 {\mu}J and pulse width of 1.18 {\mu}s at repetition rate of 63 kHz. To the best of our knowledge, this is the first time to demonstrate that black phosphorus can realize Q-switching of 2.8-{\mu}m fiber laser. Our research results show that black phosphorus is a promising saturable absorber for mid-infrared pulsed lasers.
20 Jul 2015
TL;DR: In this article, the first femtosecond fiber laser operating near 3μm was reported, based on nonlinear polarization evolution in an Er3+-doped fluoride glass fiber with an estimated peak power of 3.5kW.
Abstract: Ultrafast fiber lasers operating in the near-infrared have revolutionized laser science by enabling numerous breakthroughs in both fundamental science and industrial applications. In this Letter, we extend the spectral coverage of these laser sources to the mid-infrared by reporting the first femtosecond fiber laser operating near 3 μm. This passively mode-locked fiber ring laser based on nonlinear polarization evolution in an Er3+-doped fluoride glass fiber generates 207 fs pulses at 2.8 μm with an estimated peak power of 3.5 kW. This demonstration paves the way for further developments of promising applications in the molecular fingerprint region such as frequency comb spectroscopy.
TL;DR: Simulations show that the bandgap of WS2 nanosheets decreases from 1.18 to 0.02 and 0.65 eV by introducing W and S defects respectively, which may contribute to the broadband saturable absorption property of the WS2.
Abstract: Transition-metal dichalcogenides, such as tungsten disulfide (WS2) and molybdenium disulfide (MoS2), are highly anisotropic layered materials and have attracted growing interest from basic research to practical applications due to their exotic physical property that may complement graphene and other semiconductor materials. WS2 nanosheets are found to exhibit broadband nonlinear saturable absorption property, and saturable absorbers (SAs) are fabricated by depositing WS2 nanosheets on side-polished fibers. Attributing to the weak evanescent field and long interaction length, the WS2 nanosheets are not exposed to large optical intensity, which allows the SA to work at the high-power regime. The SAs are used to mode lock erbium- and ytterbium-doped fiber lasers with normal dispersion, producing trains of dissipative soliton at 1.55 and 1.06 µm respectively. Simulations show that the bandgap of WS2 nanosheets decreases from 1.18 to 0.02 and 0.65 eV by introducing W and S defects respectively, which may contribute to the broadband saturable absorption property of the WS2.
TL;DR: In this article, a ytterbium and erbium-doped fiber laser Q-switched by a solution processed, optically uniform, few-layer tungsten disulfide saturable absorber (WS2-SA) is characterized by 3.1% and 4.9% modulation depths with 1.38 and 3.83 MW/cm2 saturation intensities at 1030 and 1558 nm, respectively.
Abstract: We demonstrate a ytterbium (Yb) and an erbium (Er)-doped fiber laser Q-switched by a solution processed, optically uniform, few-layer tungsten disulfide saturable absorber (WS2-SA). Nonlinear optical absorption of the WS2-SA in the sub-bandgap region, attributed to the edge-induced states, is characterized by 3.1% and 4.9% modulation depths with 1.38 and 3.83 MW/cm2 saturation intensities at 1030 and 1558 nm, respectively. By integrating the optically uniform WS2-SA in the Yb- and Er-doped laser cavities, we obtain self-starting Q-switched pulses with microsecond duration and kilohertz repetition rates at 1030 and 1558 nm. Our work demonstrates broadband sub-bandgap saturable absorption of a single, solution processed WS2-SA, providing new potential efficacy for WS2 in ultrafast photonic applications.
TL;DR: This power scaling demonstration of a fiber laser operating near the vibrational resonance of water is likely to have a significant impact on several biomedical applications.
Abstract: We report the demonstration of a 2938 nm erbium-doped fluoride glass fiber laser delivering a record output power of 30.5 W in continuous wave operation. The passively cooled all-fiber laser cavity based on intracore fiber Bragg gratings has an overall laser efficiency of 16% as a function of the launched pump power at 980 nm and a single-mode output beam quality of M2<1.2. This power scaling demonstration of a fiber laser operating near the vibrational resonance of water is likely to have a significant impact on several biomedical applications.
TL;DR: The generation of a supercontinuum spanning more than 1.4 octaves in a silicon nitride waveguide using sub-100-fs pulses at 1 μm generated by either a 53-MHz, diode-pumped ytterbium fiber laser or a 1-GHz, Yb:CaAlGdO(4) (Yb:CALGO) laser is demonstrated.
Abstract: We demonstrate the generation of a supercontinuum spanning more than 1.4 octaves in a silicon nitride waveguide using sub-100-fs pulses at 1 μm generated by either a 53-MHz, diode-pumped ytterbium (Yb) fiber laser or a 1-GHz, Yb:CaAlGdO4 (Yb:CALGO) laser. Our numerical simulations show that the broadband supercontinuum is fully coherent, and a spectral interference measurement is used to verify that the supercontinuum generated with the Yb:CALGO laser possesses a high degree of coherence over the majority of its spectral bandwidth. This coherent spectrum may be utilized for optical coherence tomography, spectroscopy, and frequency metrology.
TL;DR: This work provides the first evidence for solitons involving more than a few modes, and for spatiotemporal multimode soliton fission and Raman shifting, in multimode opticalsolitons with up to roughly 10 spatial modes.
Abstract: As optical fiber communications and fiber lasers approach fundamental limits there is considerable interest in multimode fibers. In nonlinear science, they represent an exciting environment for complex nonlinear waves. As in single-mode fiber, solitons may be particularly important. Multimode solitons consist of synchronized, non-dispersive pulses in multiple spatial modes, which interact via the Kerr nonlinearity of the fiber. They are expected to exhibit novel spatiotemporal characteristics, dynamics and, like single-mode solitons, may provide a convenient intuitive tool for understanding more complex nonlinear phenomena in multimode fibers. Here we explore experimentally and numerically basic properties and spatiotemporal behaviors of these solitons: their formation, fission, and Raman dynamics.
TL;DR: The results of this experiment confirm that WS2 can be used as an effective broadband saturable absorption material that is suitable to passively generate pulses at 2 μm wavelengths.
Abstract: We demonstrate the use of an all-fiberized, mode-locked 1.94 μm laser with a saturable absorption device based on a tungsten disulfide (WS2)-deposited side-polished fiber. The WS2 particles were prepared via liquid phase exfoliation (LPE) without centrifugation. A series of measurements including Raman spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) revealed that the prepared particles had thick nanostructures of more than 5 layers. The prepared saturable absorption device used the evanescent field interaction mechanism between the oscillating beam and WS2 particles and its modulation depth was measured to be ~10.9% at a wavelength of 1925 nm. Incorporating the WS2-based saturable absorption device into a thulium-holmium co-doped fiber ring cavity, stable mode-locked pulses with a temporal width of ~1.3 ps at a repetition rate of 34.8 MHz were readily obtained at a wavelength of 1941 nm. The results of this experiment confirm that WS2 can be used as an effective broadband saturable absorption material that is suitable to passively generate pulses at 2 μm wavelengths.