We demonstrate low-threshold supercontinuum generated in a highly nonlinear arsenic selenide chalcogenide nanowire with tailored dispersion. The tapered submicrometer chalcogenide fiber exhibits an ultrahigh nonlinearity, n(2) approximately 1.1x10(-17) m(2)/W and an effective mode area of 0.48 mum(2), yielding an effective nonlinearity of gamma approximately 93.4 W/m, which is over 80,000 times larger than standard silica single-mode fiber at a wavelength of approximately 1550 nm. This high nonlinearity, in conjunction with the engineered anomalous dispersion, enables low-threshold soliton fission leading to large spectral broadening at a dramatically reduced peak power of several watts, corresponding to picojoule energy.
Application of a multilayer Molybdenum Disulfide (MoS2) thin film as a saturable absorber was experimentally demonstrated by realizing a stable and robust passive mode-locked fiber laser via the evanescent field interaction between the light and the film. The MoS2 film was grown by chemical vapor deposition, and was then transferred to a side polished fiber by a lift-off method. Intensity-dependent optical transmission through the MoS2 thin film on side polished fiber was experimentally observed showing efficient saturable absorption characteristics. Using erbium doped fiber as an optical gain medium, we built an all-fiber ring cavity, where the MoS2 film on the side polished fiber was inserted as a saturable absorber. Stable dissipative soliton pulse trains were successfully generated in the normal dispersion regime with a spectral bandwidth of 23.2 nm and the pulse width of 4.98 ps. By adjusting the total dispersion in the cavity, we also obtained soliton pulses with a width of 637 fs in the anomalous dispersion regime near the lasing wavelength λ = 1.55 μm. Detailed and systematic experimental comparisons were made for stable mode locking of an all-fiber laser cavity in both the normal and anomalous regimes.
Active manipulation of light in optical fibres has been extensively studied with great interest because of its compatibility with diverse fibre-optic systems. While graphene exhibits a strong electro-optic effect originating from its gapless Dirac-fermionic band structure, electric control of all-fibre graphene devices remains still highly challenging. Here we report electrically manipulable in-line graphene devices by integrating graphene-based field effect transistors on a side-polished fibre. Ion liquid used in the present work critically acts both as an efficient gating medium with wide electrochemical windows and transparent over-cladding facilitating light–matter interaction. Combined study of unique features in gate-variable electrical transport and optical transition at monolayer and randomly stacked multilayer graphene reveals that the device exhibits significant optical transmission change (>90%) with high efficiency-loss figure of merit. This subsequently modifies nonlinear saturable absorption characteristics of the device, enabling electrically tunable fibre laser at various operational regimes. The proposed device will open promising way for actively controlled optoelectronic and nonlinear photonic devices in all-fibre platform with greatly enhanced graphene–light interaction.
The efficient passive mode-locking of a Ti:sapphire laser with a monolayer graphene saturable absorber is demonstrated for the first time. High-quality and large-area (1 in.) monolayer graphene, synthesized by chemical vapor deposition, exhibits ultrafast recovery times and excellent nonlinear absorption behavior for bulk solid-state laser mode-locking near 800 nm. The continuous-wave mode-locked Ti:sapphire laser generates 63-fs pulses with output powers up to 480 mW under stable operation at 99.4 MHz.
High-quality monolayer graphene as large as 1.2×1.2 cm2 was synthesized by chemical vapor deposition and used as a transmitting saturable absorber for efficient passive mode-locking of a femtosecond bulk solid-state laser. The monolayer graphene mode-locked Cr:forsterite laser was tunable around 1.25 μm and delivered sub-100 fs pulses with output powers up to 230 mW. The nonlinear optical characteristics of the monolayer graphene saturable absorber and the mode-locked operation were then compared with the case of the bilayer graphene saturable absorber.
We demonstrated a Q-switched fiber laser based on Tungsten Disulfide (WS 2 ) saturable absorber. The WS 2 nano-sheets were prepared by liquid phase exfoliation method and the saturable absorber was fabricated by spin-coating of few-layer WS 2 nano-sheets on a side-polished fiber for pulsed operation of a fiber laser. By inserting the absorber into an Erbiumdoped fiber laser cavity pumped by a 980 nm laser diode, a stable Qswitched laser operation was achieved with a tunable repetition rates from 82 kHz to 134 kHz depending on the applied pump power. The properties of the deposited WS 2 film was examined using scanning electron microscopic (SEM) and atomic force microscope (AFM). Detailed optical properties of the laser output are also discussed.
We report on an Er-doped fiber pulse laser at large net normal dispersion cavity by employing a dispersion compensating fiber in combination with a single-walled carbon nanotube (SWCNT) saturable absorber. A SWCNT/polymer composite film uniformly spin-coated on the side-polished fiber is prepared for robust and efficient nonlinear interaction with evanescent fields in the waveguide expecting increase of optical and thermal damage threshold compared to previously reported direct coating of SWCNTs on fiber ferrules. The fabricated dissipative soliton fiber laser exhibits high average output power of 55.6 mW, corresponding to pulse energy about 2.35 nJ. Highly chirped 5.8 ps pulses are generated with a spectral bandwidth of 13.9 nm and compressed down to 226 fs using additional length of conventional optical fiber at extra-cavity.
We demonstrate a high-power dissipative soliton fiber laser by employing an evanescent field-coupled graphene saturable absorber (SA). In the SA, a polymer supporter enhances the nonlinear interaction between the guided mode and the high-quality graphene layers, which enables high-power operation of the mode-locked laser in the normal dispersion regime of the laser cavity. A self-started dissipative soliton fiber laser stably generates pulses with a spectral bandwidth of 10.4 nm at 1565 nm. The linearly chirped pulse of the laser output has a pulse duration of 13.8 ps at a repetition rate of 16.99 MHz. The maximum output power achieved is 174 mW using a single-mode pump laser diode with an applied power of 785 mW. The pulse energy is estimated to be 10.2 nJ; we believe this is the highest pulse energy ever reported for an Er-doped dissipative soliton fiber laser oscillator using a graphene SA.
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