Dual-wavelength Fiber Research Articles

Switchable and dual-wavelength ultrafast fibre lasers with an MoTe2-based saturable absorber

ABSTRACTBased on monolayer MoTe2 film, we have proposed a mode-locked fibre laser delivering single-wavelength and dual-wavelength solitons at the telecommunication band. The saturable absorber (SA) is synthesized by coating monolayer MoTe2 film on the pinhole of fibre pigtail. The experimental results show that our soliton lasers can work at the single- and dual-wavelength states, respectively, by appropriately adjusting the polarization controller. The proposed laser can work stably at the mode-locking state for several hours, indicating that monolayer MoTe2 film is an excellent SA material for ultrafast optics.

Dual-wavelength self-starting mode-locking Er-doped fiber laser with MnPS<sub>3</sub> saturable absorber

As a member of the metal phosphorus trichalcogenide family, MPS<sub>3</sub> is widely used in nonlinear optics and devices, which can be regarded as a significant benefit for the excellent photonic and optoelectronic properties. In this work, the MnPS<sub>3</sub> nanosheet is prepared by the chemical vapor transport method and the MnPS<sub>3</sub> saturable absorber is demonstrated by modifying mechanical exfoliation. To the best of our knowledge, the dual-wavelength self-starting mode-locking erbium-doped fiber laser with MnPS<sub>3</sub> saturable absorber is demonstrated for the first time. The dual wavelength mode-locked laser with a pulse repetition rate of 5.102 MHz at 1565.19 nm and 1565.63 nm is proposed. Its maximum output power at the dual-wavelength is 27.2 MW. The mode-locked laser can self-start and stably run for more than 280 h.

Continuously spacing-tunable dual-wavelength erbium-doped fiber laser based on polarization-dependent in-line multimode-single-mode-multimode fiber filter

A continuously spacing-tunable dual-wavelength erbium-doped all-fiber laser is proposed and experimentally demonstrated in this paper. The key component of the laser is a novel polarization-maintained multimode-single-mode-multimode fiber interference filter, which is composed of two single-mode-multimode-single-mode fiber mode converters with a polarization-maintaining fiber sandwiched between them. As the polarization-maintaining fiber gives rise to a polarization-dependent phase difference, the fiber filter shows good polarization-dependent characteristics in interference filtering. Based on the mode interference and polarization control, the good wavelength tuning results are obtained in experiment. An optimized length of 1.3 mm for multimode fiber and 1.5 mm for polarization-maintaining fiber are adopted based on the theoretical and experimental analysis. When the phase difference between the lasing in the fast axial direction and that in the slow axial direction is <inline-formula><tex-math id="M1">\begin{document}$ {\text{π}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="15-20190297_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="15-20190297_M1.png"/></alternatives></inline-formula>, the peaks and valleys in the transmission spectrum of the fiber filter correspond exactly to the two orthogonal polarization states. In the test, when the pump power is 50 mW, a high-quality dual-wavelength lasing output (at 1544.82 nm and 1545.61 nm) is observed to have side-mode suppression ratio better than 45 dB, the wavelength spacing of 0.8 nm, the peak power difference of less than 1 dB, and the output keeps stable with a small power fluctuation less than 0.7 dB. By adjusting the polarization controller in the ring cavity, two different dual-wavelength outputs can be obtained, which are corresponding to tuning Ⅰ and tuning Ⅱ. In tuning Ⅰ, a dual-wavelength lasing output in a wavelength spacing tuning range of 0−1.2 nm can be obtained within 1 dB peak power difference, correspondingly, 0−1.6 nm tuning range within 10 dB peak power difference. In tuning Ⅱ, with continuously adjusting the polarization controller, the short wavelength signal of the dual-wavelength output stops resonating, and simultaneously another wavelength signal near 1547.8 nm is excited, the switching is continuous and the system remains dual-wavelength output. In tuning Ⅱ, a maximum tuning range of 1.6−3 nm is obtained. In both of tuning Ⅰ and tuning Ⅱ, a 0−3 nm continuously spacing-tunable dual-wavelength output is obtained, all of which keep stable single-polarization operation. The test results show that the polarization state of the dual-wavelength lasing varies with tuning; a maximum polarization extinction ratio of 35 dB is obtained as the two wavelengths are orthogonally polarized.

High-birefringence dual-wavelength single-polarization photonic crystal fibre polarizing filter based on surface plasmon resonance

ABSTRACTA dual communication band single-polarization photonic crystal fibre polarizing filter based on surface plasmon resonance is presented in this paper. Numerical simulation results demonstrate that the resonance strength of x- and y-polarized direction can reach 569.83 and 719.25 dB.cm−1 simultaneously at the communication wavelength of 1.31 and 1.55 µm. By filling liquid analyte, the confinement loss of x- and y-polarized direction can simultaneously reach 831.7 and 580.53 dB.cm−1 at the wavelength of 1.31 and 1.55 µm. Furthermore, when the fibre length L is equal to 700 µm, the peak value of the crosstalk can reach 493.86 and −323.67 dB at the same time at the wavelength of 1.31 and 1.55 µm, and when the length of the fibre L is 400 µm, the bandwidths of the crosstalk better than 20 dB and less than −20 dB are about 160 and 210 nm, respectively. These performances make it an ideal candidate for designing dual-band polarization filter equipment.

Dual-wavelength mode-locked Er-doped fiber laser based on optimizing gain fiber length

Recently,multi-wavelength pulsed lasers have become a research hotspot due to their versatile applications,such as precision spectroscopy,microwave/terahertz photonics,optical signal processing,and wavelength division multiplexed optical fiber communication systems.As a promising candidate,passively mode-locked fiber laser has the advantages of ultrashort pulse,ultrahigh peak power,compact structure and low-cost.In the existing multi-wavelength passively mode-locked fiber lasers,multi-wavelength mode-locked operation is achieved by adjusting the intracavity modulators to a proper state after laser has worked.It is inconvenient for practical use,so,its application scope is restricted.In this paper,a new method to achieve dual-wavelength mode-locked operation in an erbium-doped fiber laser is proposed. For an erbium-doped fiber,the peaks of both absorption and emission spectra overlap in the 1530 nm-region.So the emission light in the 1530 nm-region will be re-absorbed by the erbium-doped fiber with low pump power or long gain fiber.Utilizing the emission re-absorption effect,the gain spectrum can be modified by different lengths of gain fiber. In the experiment,an all-fiber ring cavity is adopted and a transmission-type semiconductor saturable absorber is used as a modelocker.The cavity consists of ～3.2-m-long single mode fiber and an erbium-doped fiber.Gain fibers with different lengths are used in the cavity to reveal the dependence of emission re-absorption on both gain spectrum and mode-locked output spectrum.According to the experimental results,there are two humps in the amplified spontaneous emission spectrum located in the 1530 nm-region and 1560 nm-region,respectively.With the gain fiber length increasing, gain spectrum in the 1530 nm-region is suppressed,and gain intensity in the 1560 nm-region gradually surpasses that in the 1530 nm-region.Based on the experimental results,self-starting dual-wavelength mode-locked operation is achieved with a 31-cm-long gain fiber.The two spectral peaks with close intensity are located at 1532.4 nm and 1552.3 nm, respectively.The maximum output power is 4.8 mW at a repetition rate of 58.01 MHz and a signal-to-noise ratio of 58.2 dB.This self-starting dual-wavelength mode-locked erbium-doped fiber laser is convenient for practical use and can meet the requirements for many potential applications.

Stability wavelength-spacing-tunable single-longitudinal-mode dual-wavelength erbium-doped fiber laser based on nonlinear amplifying loop mirror

A simple linear cavity configuration for a stability wavelength-spacing-tunable single-longitudinal-mode (SLM) dual-wavelength erbium-doped fiber laser based on a nonlinear amplifying loop mirror (NALM) is proposed. The gain competition in the erbium-doped fiber (EDF) has been suppressed by the intensity dependent loss introduced by the NALM. The SLM operation is guaranteed by a section of unpumped EDF as saturable absorber. A stable dual-wavelength SLM fiber laser with a wavelength-spacing of 11.35 nm is experimentally realized. The optical signal-to-noise ratio is over 47 dB and the linewidths of two wavelengths measured by delayed self-heterodyne method are 1.1 and 1.0125 kHz, respectively. The tuning range of wavelength-spacing is 9.09–11.35 nm, correspondingly, and the THz signal is from 1.235 to 1.416 THz.

Tunable and switchable dual-wavelength erbium-doped fiber laser based on in-line tapered fiber filters

A tunable and switchable dual-wavelength erbium-doped fiber laser (EDFL) based on all-fiber single-mode tapered fiber structure has been demonstrated. By adjusting the variable optical attenuator (VOA), the laser can be switched between the single-wavelength mode and the dual-wavelength mode. When the temperature applied on the tapered fiber structure varies, the pass-band varies and the wavelength of the output laser shifts correspondingly. When the temperature changes from 30 °C to 180 °C, the central wavelength of the EDFL generated by branch A shifts from 1 550.7 nm to 1 560.3 nm, while that of branch B shifts from 1 530.8 nm to 1 540.4 nm, indicating the wavelength interval is tunable. These advantages enable this laser to be a potential candidate for high-capacity wavelength division multiplexing systems and mechanical sensors.

Compact dual-wavelength thulium-doped fiber laser employing a double-ring filter

In this paper, we report on stable dual-wavelength operation of a thulium-doped compact all-fiber laser using a double-ring filter as the wavelength selective element. Simultaneously lasing at 2014.4 and 2018.4nm has been obtained via tuning the polarization controllers to adjust the relative gain and loss of the laser cavity. The side mode suppression ratios are greater than 52dB and the output power difference between the two lasing lines is less than 0.08dB under 2.6W of incident pump power.

Single-/dual-wavelength switchable and tunable compound-cavity erbium-doped fiber laser with super-narrow linewidth

A single-/dual-wavelength switchable and tunable erbium-doped fiber laser (EDFL) with super-narrow linewidth has been proposed and experimentally demonstrated at room temperature. The fiber laser is based on a compound cavity simply composed of a ring main cavity and a two-ring subring cavity (TR-SC). Regardless of single- or dual-wavelength operation, the EDFL could always work well in single-longitudinal-mode (SLM) state at every oscillating wavelength. In dual-wavelength operation, the spacing could be tuned from 0 nm to 4.83 nm. In single-wavelength operation, the EDFL could lase at a fixed wavelength of 1 543.65 nm or another wavelength with a tunable range of 4.83 nm. The super-narrow linewidths of 550 Hz and 600 Hz for two wavelengths are obtained. The proposed EDFL has potential applications in microwave/terahertz-wave generation and high-precision distributed fiber optical sensing.

Passively dual-wavelength Q-switched ytterbium doped fiber laser using Selenium Bismuth as saturable absorber

This paper describes a demonstration of a passively dual-wavelength Q-switched ytterbium-doped fiber laser using a selenium bismuth-based saturable absorber. By utilizing a short-length photonic crystal fiber in a ring cavity and performing adjustments to the polarization state of an incorporated polarization controller (PC), we obtained a stable dual-wavelength Q-switched output at 1037.14 and 1037.69 nm, with maximum pulse energy of 0.65 nJ, shortest pulse width of 8.46 μs, and pulse repetition rate from 15.37 to 59.24 kHz. The Q-switched laser output consistently achieved high-power stability with a 0.8 dB maximum fluctuation over a period of 20 min.

Tunable dual-wavelength thulium-doped fiber laser at 1.8 μm region using spatial-mode beating

This study describes a proposal and experimental demonstration of a tunable thulium-doped fiber laser with a multi-wavelength output operating at 1.8 μm. The introduction of a multi-mode non-adiabatic taper fiber into a single-mode cavity induces spatial-mode beating and a consequent narrow band filter mechanism. The fiber laser can be tuned by changing the state of the polarization in a ring cavity via adjustment of a polarization controller. The resulting outputs for single and dual wavelengths with different spacing are reported in detail.

基于光纤环形滤波器的双波长掺铒光纤激光器

基于光纤环形滤波器的双波长掺铒光纤激光器

A switchable dual-wavelength erbium-doped fiber laser based on saturable absorber and active optical fiber ring filter

A dual-wavelength erbium-doped fiber laser (EDFL) with outstanding stability is presented. In the fiber laser system, two nested active optical fiber ring filters are configured to improve the comb spectrum performance, a saturable absorber is employed to form a gain grating for both filtering and frequency stabilizing, two cascaded fiber Bragg gratings (FBGs) are utilized to achieve dual-wavelength output, and a variable attenuator is arranged to adjust output power. Experimental results illustrate that the peak wavelength drift is less than 3 pm, and a good linear relationship between output power and pump power is realized.

A dual-wavelength erbium-doped fiber laser with widely tunable wavelength spacing

A stable dual-wavelength erbium-doped fiber laser (EDFL) with tunable wavelength spacing and equalized output power is proposed and experimentally demonstrated. The fiber laser uses two fiber Fabry-Perot tunable filters (FFPTFs) as the wavelength filter. The main cavity is divided into two sub-cavities with imbalance cavity losses through a 30/70 optical coupler. The tunable wavelength spacing can be achieved by changing the center wavelength of the filters and the equalized dual-wavelength output power can be achieved by properly controlling the variable optical attenuator (VOA) inserted in the lower-loss cavity.

The Evolution of Dual-Wavelength Dissipative Soliton in Yb-Doped Fiber Lasers

Dual-wavelength dissipation soliton (DS) in the all-normal-dispersion ytterbium-doped fiber laser (YDFL) is reported. Using a phase-shift long period fiber grating (PS-LPFG) as an all-fiber format spectral filter in the laser cavity, self-starting dual-wavelength pulses are obtained by nonlinear polarization evolution (NPE). The mode-locking mechanism of the ANDi cavity with different central wavelengths has analyzed. Experimental results show that the NPE together with the PS-LPFG play key roles in the generation of the dual-wavelength, meanwhile, a switchable dual-wavelength mode-locked fiber laser can achieve through change the polarization of the cavity. DOI: http://dx.doi.org/10.11591/telkomnika.v11i10.2961

Dual-wavelength DFB Fiber Laser based Equivalent Phase Shift

Abstract A new structured dual-wavelength distributed feedback fiber laser is proposed. In this new structure, phase shift is introduced as well as equivalent phase shift. Theoretical analysis and simulation demonstrates this new structure is able to provide separate resonant cavities to overcome mode competition. Different channels of sampled fiber Bragg gratings are utilized simultaneously, so wide wavelength spacing could be achieved. A 31 GHz spaced dual-wavelength DFB fiber laser is achieved on an Er-doped fiber with excimer laser and homogeneous phase plate. Experiments shows that dual-wavelength lasing is achieved and laser power is in reverse proportion with coupling coefficient of the FBG.

Dual-Wavelength Single-Mode Optical Fiber Raman Laser

In order to realize the dual-wave length lasing based on stimulated Raman scattering principle, the dual-wavelength single-mode optical fiber Raman laser is established. Firstly, 80m long G652b single-model quartz fiber is pumped by Nd3+:YAG solid pulse laser, and its output spectra when without grating which are measured and studied. Then, a linear external-cavity fiber laser is designed with fiber Bragg grating as mirrors to gain 1062nm and 1066.5nm laser output. To change pump energy (65.2uJ~100.4uJ), the mean-variances of energy percentages are all about 7.58%,and dual-wavelength energy ratio is close to 1:1. Pump pulse widths are close to 32.14ns. Finally, the main parameters of laser are analyzed too. The dual-wavelength single-mode optical fiber Raman laser can be applied to Raman amplifier filed.

Investigation of Dual-Wavelength Erbium-Doped Fiber Laser Intra-Cavity Absorption Sensor

We propose a dual-wavelength intra-cavity absorption sensor based mode competition. The sensitivity of output power to relative cavity loss in different pump current is studied experimentally by defining a sensitivity enhancement factor (SEF). A measurement sensitivity of 158.5 times that of a single-pass absorption sensor is achieved.

A novel sensor based on a dual-wavelength multilongitudinal modes fiber ring laser

A ring laser based on a transmission-type fiber bragg grating (FBG)-Fabry–Perot filter sensor probe is proposed, and ignoring the effect of multilongitudinal modes using a special demodulation method, the new scheme is suitable for long distance sensing. Such a sensing system has been demonstrated in the experiment, and the experimental result shows the minimal temperature sensitivity is about 1°C. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:15–16, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27254

Switchable dual-wavelength SOA-based fiber laser with continuous tunability over the C-band at room-temperature

We propose and demonstrate a simple compact, inexpensive, SOA-based, dual-wavelength tunable fiber laser, that can potentially be used for photoconductive mixing and generation of waves in the microwave and THz regions. A C-band semiconductor optical amplifier (SOA) is placed inside a linear cavity with two Sagnac loop mirrors at its either ends, which act as both reflectors and output ports. The selectivity of dual wavelengths and the tunability of the wavelength difference (Δλ) between them is accomplished by placing a narrow bandwidth (e.g., 0.3 nm) tunable thin film-based filter and a fiber Bragg grating (with bandwidth 0.28 nm) inside the loop mirror that operates as the output port. A total output power of + 6.9 dBm for the two wavelengths is measured and the potential for higher output powers is discussed. Optical power and wavelength stability are measured at 0.33 dB and 0.014 nm, respectively.