Erbium-doped Fiber Laser System Research Articles

Characterization of sub-20-attosecond timing jitter in erbium-doped fiber laser system

The significance of timing jitter stems from its pivotal role in enhancing the precision of applications like spectroscopy and frequency metrology. In this study, we introduce a comprehensive procedure for achieving low timing jitter values in mode-locked fiber laser systems, highlighting dispersion, intracavity pulse energy, pulse length, and spectral bandwidth as key parameters. Notably, we unveil the influence of fiber amplifier pump power on jitter, a factor neglected in established theories and recent experiments. Applying this procedure to a 200-MHz all-polarization-maintaining (PM) erbium-doped (Er:) nonlinear amplifying loop mirror (NALM) fiber laser system, we demonstrate an exceptionally low timing jitter of 14.25 attoseconds, measured using the balanced optical cross-correlation (BOC) technique and integrated from 10 kHz to 4 MHz. The implementation of our novel method offers the opportunity to improve jitter results in various fiber laser systems and increase the accuracy of fiber laser applications.

Switchable multi-wavelength fiber laser based on a taper-coupled microbottle resonator

A multi-wavelength erbium-doped fiber laser (EDFL) based on a taper-coupled microbottle resonator is proposed and investigated experimentally. The taper-coupled microbottle resonator has the comb filter characteristics with Q factor 2.9 × 104, which is integrated into an EDFL system. The taper-coupled microbottle resonator was packaged by ultraviolet glue, which has excellent stability of output power and wavelength at room temperature. Then, switchable dual-, triple-, quad- and quint-wavelength fiber laser states can be achieved by adjusting the polarization controller (PC). Furthermore, for dual-wavelength and triple-wavelength laser state, the position of output wavelengths also can be precisely modulated with the PC. The developed multi-wavelength EDFL has the optical signal to noise ratio as high as 40 dBm, and the wavelength shift and peak power fluctuation are less than 0.03 nm and 6 dBm.

In2Se3 nanosheets with broadband saturable absorption used for near-infrared femtosecond laser mode locking

Indium selenide (In2Se3) has attracted tremendous attention due to its favorable electronic features, broad tunable bandgap, high stability and other attractive properties. However, its further applications for nonlinear optics have not yet been fully explored. In this work, we demonstrate that few-layer α-In2Se3 nanosheets exhibit strong saturable absorption properties over a wide wavelength range covering 800, 1064 and 1550 nm. The few-layer α-In2Se3 nanosheets used for this experiment are fabricated via a simple ultrasonic exfoliation in liquid. Stable ultrafast mode-locking laser pulses are obtained from both ytterbium-doped and erbium-doped fiber laser systems operating at 1064 and 1550 nm, respectively. A pulse duration as short as 215 fs was achieved in the Er-doped fiber laser system. Stable output pulses over 6 h of operation were obtained in both laser systems. The pulse energy and peak power of the laser output pulses were increased by reducing the In2Se3 thickness. These results indicate that α-In2Se3 nanosheets with low layer numbers are promising candidates for broad ultrafast photonics devices, such as optical switchers, Q-switchers and mode lockers.

Power Fluctuations and Random Lasing in Multiwavelength Brillouin Erbium-Doped Fiber Lasers

We experimentally and theoretically investigate the power fluctuations of the temporal interference signal produced by up to 5 Stokes orders generated by cascaded stimulated Brillouin scattering in a multiwavelength Brillouin erbium-doped fiber laser system with a 2.5-km-long intracavity fiber and erbium-doped fiber amplifier. Power fluctuations in such a system are due to the existence of several modes within the SBS gain bandwidth with the possibility of random hopping resulting in a chaotic temporal evolution of the pump and Stokes-wave powers and consequently the output signal power. Our simulations and statistical analyses show that at the threshold power resulting in the initial Stokes wave generation over round trips, the output signals have the maximum correlation over replicas; however, by increasing the power and producing more stokes waves, the correlation fades out leading to replica symmetry breaking and the system emits in a disordered manner and shows the signatures of a random laser.

Mode-locked fiber laser in the C-band region for dual-wavelength ultrashort pulses emission using a carbon nanotube saturable absorber

A saturable absorber is commonly employed to generate an ultrashort laser with a mode-locking scheme. In an erbium-doped fiber laser system, the laser regimes of either 1530 or 1550 nm wavelength are procured based on the absorption profile of the erbium-doped fiber. The absorption of the erbium-doped fiber is designed to emit at both wavelengths by controlling the net gain of the laser cavity. Subsequently, simultaneous erbium-doped fiber laser emission is attained at 1533.5 and 1555.1 nm with the pulse duration of 910 and 850 fs, respectively. Therefore, this work maximizes the output portfolios of a mode-locking fiber laser for dual-wavelength ultrashort pulses emission.

Q-switched laser generation using MoWS[formula omitted]-rGO in Erbium-doped fiber laser cavity

A saturable absorber (SA) consisting of a Mo(1−x)WxS2-rGO composite is proposed and fabricated, and its performance demonstrated. The fabricated Mo(1−x)WxS2-rGO has an x composition of 0.2 and is incorporated into a polymer composite thin film. Nonlinear optical characterization of the SA reveals that the Mo(1−x)WxS2-rGO/PVA thin film exhibits a relatively high modulation depth of ∼5.9% and low saturation intensity of 0.003 MW/cm2. The Mo(1−x)WxS2-rGO/PVA thin film SA has an improved optical absorption as well as enhanced photo response, allowing it to generate tunable Q-switched outputs over a range of 56 nm from 1518 nm to 1574 nm in Erbium-doped fiber laser systems. At the optimum lasing wavelength of ∼1560 nm, the highest pulse repetition rate, narrowest pulse width, highest output power and highest pulse energy is achieved at 64.82 kHz, 1.47 μs, 0.37 mW and 5.98 nJ, respectively. The proposed laser would have significant applications in biomedical imaging, material processing environmental sensing and range finding.

Transition-metal dichalcogenides heterostructure saturable absorbers for ultrafast photonics.

In this Letter, high-quality WS2 film and MoS2 film were vertically stacked on the tip of a single-mode fiber in turns to form heterostructure (WS2-MoS2-WS2)-based saturable absorbers with all-fiber integrated features. Their nonlinear saturable absorption properties were remarkable, such as a large modulation depth (∼16.99%) and a small saturable intensity (6.23 MW·cm-2). Stable pulses at 1.55μm with duration as short as 296fs and average power as high as 25mW were obtained in an erbium-doped fiber laser system. The results demonstrate that the proposed heterostructures own remarkable nonlinear optical properties and offer a platform for adjusting nonlinear optical properties by stacking different transition-metal dichalcogenides or modifying the thickness of each layer, paving the way for engineering functional ultrafast photonics devices with desirable properties.

Dynamics of Stokes Waves and Pulses Generated by Stimulated Brillouin Scattering in a Resonator Including Highly Nonlinear Fiber

We experimentally and theoretically investigate the generation of Stokes waves and the dynamics of pulses produced by cascaded stimulated Brillouin scattering (SBS) in a resonator, including a highly nonlinear fiber (HNLF) and an in-cavity erbium-doped fiber amplifier (EDFA) forming a multi-wavelength Brillouin erbium-doped fiber laser system. Using coupled wave equations with the Brillouin pump, Stokes and acoustic waves, propagation in the presence of the SBS and optical Kerr effect, the modeled system simulates the evolution of participating pump and Stokes waves to verify the experimental results. The dependence of the number of generated Stokes waves on EDFA pump and Brillouin pump powers is studied showing that the proper simultaneous change (increase or decrease) of the two pump powers over few hundred of milliwatts (using the power design diagram) results in generating the same number of Stokes waves reaching steady state. Dynamics of the interference signal at the resonator output are also presented for a long HNLF (33 m) showing strong instability due to the existence of a few longitudinal modes within the SBS gain bandwidth with the possibility of random mode hopping. For a short HNLF (3 m), a single longitudinal mode operation is possible and the stability of generated pulses is expected but still depends on the phase relationships per round trip of the participating pump and Stokes waves. A good consistency between simulation and experiment is found.

Generation of stable cnoidal waves in an erbium doped fiber laser system

In this work an all-fiber laser system able to produce stable cnoidal waves in both limits, i.e. in sinusoidal and soliton limits, is presented. The system is constructed using an erbium highly-doped fiber as an active media and an electrooptic modulator as the core of the control tool. This control tool is able to modulate the cavity losses. The direct modulation allows to control the pulses properties, shape, width and intensity. The proposed system is well described by a three level laser model based on the Statz-de Mars rate equations. Numerical and Experimental results are presented.

Dissipative Soliton Generation and Amplification in Erbium-Doped Fibers Operating at 1.55 μm

We report on our recent developments on ultrafast pulse generation in erbium-doped fiber laser systems operating in the 1550 nm wavelength range. This work concerns the generation of ultrafast pulses from dissipative soliton fiber lasers featuring resonant saturable absorber mirrors as well as their amplification in highly efficient erbium-doped large-mode-area fibers. Different amplification schemes featuring all-fiber components are studied leading to the achievement of record pulse energy from a high repetition rate laser system. The system delivers 8 W of average power at 35 MHz repetition rate corresponding to 230 nJ pulse energy. After external compression, near transform-limited, 850 fs-long pulses are obtained. The pulse peak power exceeds 180 kW.

1.55-μm wavelength ultrafast fiber oscillators and amplifiers

In this paper, we review our recent developments on ultrafast pulse generation in erbium-doped fiber laser systems operating in the 1550 nm wavelength range. This work concerns the generation of ultrafast pulses from dissipative soliton fiber lasers featuring resonant saturable absorber mirrors, as well as their amplification in highly efficient erbium-doped large-mode-area fibers. Different amplification schemes featuring all-fiber components are studied leading to the achievement of record pulse energy from a high repetition rate laser system.

Erbium - doped fiber laser systems: Routes to chaos

Erbium-doped fiber laser systems exhibit a large variety of complex dynamical behaviors, bifurcations and attractors. In this paper, the chaotic behavior which can be achieved under certain conditions in a laser system with erbium-doped fiber, is discussed. The chaos in this system occurs through several standard scenarios. In this paper, the simulation sequence of quasiperiodic, intermittent and period-doubling scenario transitions to chaos is shown. Quasiperiodic and intermittent transitions to chaos are shown on the example system with a single ring. The electro-optical modulator was applied to the system for modulating the loss in the cavity. We used the sinusoidal and rectangular signals for modulation. Generation of chaos is achieved by changing the parameters of signal for modulation. Period-doubling transition to chaos is illustrated in a system with two rings. Simulation results are shown in the time domain and phase space.

Effect of Attenuation on Four-Wave Mixing Generation

Four-wave mixing (FWM) phenomenon can be produced by using a different refractive index of the optical fiber in an erbium doped fiber laser system. In our study, we used a 20 meter length of Photonics crystal fiber (PCF) to generate multiwavelength signals. Variable optical attenuator is employed in the setup to study its effect on the output signals. Results show that uniform signals were obtained by using the VOA to suppress other modes of wavelengths which occurred before placing the VOA. New lasing wavelength at 1530.445 nm, 1531.450 nm, 1531.960 and 1532.415 nm were produced uniformly.

Research on image encryption based on Erbium-doped fiber laser system with optical delay feedback

A novel image encryption algorithm that based on Erbium-doped fiber laser with an optical delay feedback (ODF-EDFL) system is proposed in this paper. First, by the dynamic analysis of this system, two different chaotic sequences are generated. Meanwhile, the statistic characteristic is verified on this chaotic sequence. On this basis, the image encryption algorithm is designed by using this chaotic sequence: the gray value of the original image is substituted with the chaotic sequence at beginning; then the space array of the image's pixel is mixed up by using both two chaotic sequences. The experimental results show that the proposed method can encrypt digital images quickly and effectively.

Eyelid Tightening and Improved Eyelid Aperture through Nonablative Fractional Resurfacing

The effects of fractional resurfacing on eyelid tightening and aperture are unknown. Our purpose was to retrospectively examine the potential for eyelid tightening and eye-aperture opening in patients treated with nonablative fractional resurfacing for facial photorejuvenation. Fractional laser treatments using a 1,550-nm erbium-doped fiber laser system on the upper and lower eyelids were given at a pulse energy of 17 to 20 mJ at 125 micro-thermal zones (MTZ)/cm(2) to a final density of 500 to 750 MTZ/cm(2). Each patient had 3 to 7 treatments. Standard pre- and post-treatment photographs were taken at each visit. Physicians who graded 31 preselected patient photographs using a 4-point scale evaluated eyelid tightening. Increase in eyelid aperture was also evaluated. All patients had some degree of eyelid tightening; 19% achieved 1% to 25% tightening, 26% achieved 25% to 50%, 26% achieved 50% to 75%, and 29% achieved 75% to 100%. Increase in eyelid aperture was seen in 55.9% of patients. Postoperative wounding, hypopigmentation, hyperpigmentation, persistent erythema, and scarring were not observed. All patients experienced mild or no edema for a few days after treatment. Fractional resurfacing tightens and increases eyelid aperture without wounding, downtime, or long-term complications.

Phase-locked two-branch erbium-doped fiber laser system for long-term precision measurements of optical frequencies

We present a highly versatile approach to the application of femtosecond Er:fiber lasers in optical frequency metrology. Our concept relies on the implementation of two parallel amplifiers, seeded by a single master oscillator. With the comb spacing locked to a frequency of 100 MHz, we apply the output from the first amplifier to generate a feedback signal to achieve a simultaneous phase-lock for the comb offset frequency. The output of the independently configurable second amplifier enables precision frequency measurements in the visible and near-infrared. As a first application, we continuously measure the absolute frequency of a resonator-stabilized diode laser over a period of 88 hours.

Chaos synchronization characteristics in erbium-doped fiber laser systems

Chaos synchronization characteristics in the master–slave and slave–slave systems with modulated erbium-doped fiber lasers are investigated numerically. We find that synchronization state of chaos becomes better, i.e., the correlation coefficient between the two outputs reaches unity, as the difference in the input power between the two subsystems decreases and is not dependent strongly upon the difference in the modulation index in both the master–slave and slave–slave systems. In the master–slave system, the highest correlation coefficient is attained at the smaller pump power and the larger modulation index in the slave subsystem than those in the master subsystem. On the other hand, the correlation coefficient equal to unity is achieved with the identical parameters in the slave 1 and 2 subsystems in the slave–slave system.

Soliton versus nonsoliton operation of fiber ring lasers

To date most passively mode-locked erbium-doped fiber laser systems have employed solitons for short pulse generation, and ultrashort high energy pulses have been difficult to achieve. We show that by reducing the system nonlinearity via pulse stretching and employing net positive dispersion cavities, pulses of sub-100-fs duration and ≳100 pJ energy are readily generated. Data are presented for varying net dispersion in a fiber ring.