Pulses In Erbium-doped Fiber Laser Research Articles

Facile active control of a pulsed erbium-doped fiber laser using modulation depth tunable carbon nanotubes

Short pulsed fiber lasers have been widely made using single-walled carbon nanotubes as a saturable absorber (SA). However, most of the currently used devices can only operate in one determined operation state with an unchangeable modulation SA depth in the cavity, which significantly limits their application in photonic devices. In this paper, well-aligned carbon nanotube arrays are synthesized using zeolite AlPO4-5 as a template, which features anisotropic optical absorption. The linear optical absorption of the as-synthesized carbon nanotube arrays can easily be tuned by adjusting a polarization controller, thus providing a tunable modulation depth for the carbon nanotube SA. By exploiting this SA in an erbium-doped fiber laser cavity, both Q-switched and mode-locked pulsed lasers are achieved by simply adjusting a polarization controller under a fixed pump power of 330 mW. In addition, the repetition rate of the Q-switching and pulse duration of the mode-locking can be tuned according to the variation of modulation depth. Moreover, soliton molecules can be obtained when the modulation depth of the SA is 4.5%.

Noise-like pulse erbium-doped fiber laser for supercontinuum generation

Two kinds of noise-like pulse bunches are observed in an erbium-doped fiber ring laser for the first time. Picosecond- and submicrosecond-scale pulse bunches with energy of 0.32 nJ and 7.1 nJ, respectively, are generated and used in super-continuum generation. Using a 50-m dispersion-shifted fiber (DSF) a 20-dB bandwidth of over 750 nm is obtained.

Pure antimony film as saturable absorber for Q-switched erbium-doped fiber laser

This paper reports on the use of Antimony (Sb) polymer film to generate stable Q-switching pulses in Erbium-doped fiber laser (EDFL) cavity. The SA is fabricated by coating a thin layer of Sb on a polyvinyl alcohol (PVA) film through physical vapour deposition (PVD) process. A 1 × 1 mm area of the film SA is cut and integrated into between two fiber ferrules inside the laser cavity for intra-cavity loss modulation. Self-starting and stable Q-switched pulses are obtained within a pump power range from 60 to 142 mW. Within this range, the repetition rate increases from 70.82 to 98.04 kHz, while pulse width decreases from 7.42 to 5.36 μs. The fundamental frequency signal-to-noise ratio of the pulse signal is 74 dB, which indicates the excellent stability of the pulses. The maximum output power and pulse energy are 8.45 mW and 86.19 nJ, respectively. Our demonstration shows that Sb film SA capable of generating stable pulses train operating at 1.55-micron region.

Q-switched fiber laser with tungsten disulfide saturable absorber prepared by drop casting method

We experimentally demonstrate a passively Q-switched erbium-doped fiber laser (EDFL) operation by using a saturable absorber (SA) based on tungsten disulfide (WS2). By depositing WS2 thin film layer at the end of optical fiber ferrule, we fabricated a SA device. The SA is incorporated into an Erbium-doped fiber laser (EDFL) cavity to generate a Q-switching pulses train operating at 1559.8 nm. As a result, stable passively Q-switched EDFL pulses with maximum output pulse energy of 123.2 nJ, repetition rate of 104.1 kHz, and pulse width of 9.61 us are achieved when the input pump power is 142.1 mW at the wavelength of 980 nm. Full Text: PDF ReferencesC. Gao, W. Zhao, Y. Wang, S. Zhu, G. Chen, and Y. Wang, "Passive Q-switched fiber laser with SESAM in ytterbium-doped double-clad fiber", in 27th International congress on High-Speed Photography and Photonics (International Society for Optics and Photonics, 2007). CrossRef M. Ahmed, N. Ali, Z. Salleh, A. Rahman, S. Harun, M. Manaf, et al., "Q-switched erbium doped fiber laser based on single and multiple walled carbon nanotubes embedded in polyethylene oxide film as saturable absorber", Optics & Laser Technology 65, 25 (2015). CrossRef M. A. Ismail, F. Ahmad, S. W. Harun, H. Arof and H. Ahmad, "A Q-switched erbium-doped fiber laser with a graphene saturable absorber", Laser Phys. Lett. 10, 025102 (2013). CrossRef G. Sobon, J. Sotor, J. Jagiello, R. Kozinski, K. Librant, M. Zdrojek, L. Lipinska, and K. M. Abramski, "Linearly polarized, Q-switched Er-doped fiber laser based on reduced graphene oxide saturable absorber", Appl. Phys. Lett. 101, 241106 (2012). CrossRef N. H. M. Apandi, F. Ahmad, S. N. F. Zuikafly, M. H. Ibrahim, S. W. Harun, "Bismuth (III) Telluride (Bi2Te3) topological insulator embed in PVA as passive Q-switcher at 2 micron region", Photon. Lett. of Poland 8, 101 (2016). CrossRef J. Bogusławski, G. Soboń, K. Tarnowski, R. Zybała, K. Mars, A. Mikuła, K. M. Abramski and J. Sotor, "All-polarization-maintaining-fiber laser Q-switched by evanescent field interaction with Sb2Te3 saturable absorber", Optical Engineering 55, 081316 (2016). CrossRef Z. Luo, Y. Huang, M. Zhong, Y. Li, J. Wu, B. Xu, H. Xu, Z. Cai, J. Peng, and J. Weng, "1-, 1.5-, and 2-um fiber lasers Q-switched by a broadband few-layer MoS2 saturable absorber", J. Lightwave Technol. 32, 4679 (2014). CrossRef N. N. Razak, A. A. Latiff, Z. Zakaria and S. W. Harun, "Q-switched Erbium-doped Fiber Laser with a Black Phosphorus Saturable Absorber", Photon. Lett. of Poland 9, 72 (2017). CrossRef D. Mao, Y. Wang, C. Ma, L. Han, B. Jiang, X. Gan, S. Hua, W. Zhang, T. Mei, and J. Zhao, "WS2 mode-locked ultrafast fiber laser", Sci Rep 5, 7965 (2015). CrossRef K. Wu, X. Zhang, J. Wang, X. Li, and J. Chen, "WS2 as a saturable absorber for ultrafast photonic applications of mode-locked and Q-switched lasers", Optics Express 23, 11453 (2015). CrossRef K. Lau, A. Latif, M. A. Bakar, F. Muhammad, M. Omar, and M. Mahdi, "Mechanically deposited tungsten disulfide saturable absorber for low-threshold Q-switched erbium-doped fiber laser", Applied Physics B 123, 221 (2017). CrossRef H. Chen, Y. Chen, J. Yin, X. Zhang, T. Guo, and P. Yan, "High-damage-resistant tungsten disulfide saturable absorber mirror for passively Q-switched fiber laser", Optics Express 24, 16287 (2016). CrossRef J. Lin, K. Yan, Y. Zhou, L. Xu, C. Gu, and Q. Zhan, "Tungsten disulphide based all fiber Q-switching cylindrical-vector beam generation", Applied Physics Letters 107, 191108 (2015). CrossRef H. Chen, Y. Chen, J. Yin, X. Zhang, T. Guo, and P. Yan, "High-damage-resistant tungsten disulfide saturable absorber mirror for passively Q-switched fiber laser", Optics Express 24, 16287 (2016). CrossRef K. Mohamed, B. Hamida, S. Khan, L. Hussein, M. Ahmat, E. Ismail, N. Kadir, A. Latif, S. Harun, "Q-switched erbium-doped fibre laser based on molybdenum disulfide and tungsten disulfide as saturable absorbers," Ukrainian Journal of Physical Optics, 18 (2017). CrossRef

Passively Q-switched erbium-doped fiber laser using Fe3O4-nanoparticle saturable absorber

We experimentally demonstrate passively Q-switched erbium-doped fiber laser (EDFL) operation using a saturable absorber (SA) based on Fe3O4 nanoparticles (FONPs). As a type of transition metal oxide, the FONPs have a large nonlinear optical response and fast response time. The FONP-based SA possesses a modulation depth of 8.2% and nonsaturable absorption of 56.6%. Stable passively Q-switched EDFL pulses with an output pulse energy of 23.76 nJ, a repetition rate of 33.3 kHz, and a pulse width of 3.2 µs were achieved when the input pump power was 110 mW. The laser features a low threshold pump power of ∼15 mW.

Pulsed erbium-doped fiber laser by a few-layer molybdenum disulfide saturable absorber: from Q-switching to mode-locking

Abstract. Wedemonstrated a pulsederbium-doped fiber laser (EDFL)based on a few-layer molybdenum disul-fide saturableabsorber(MoS 2 -SA). The MoS 2 -SA wasfabricated intoa film structure by evaporatingthe mixtureof MoS 2 nanosheets and polyvinyl alcohol. The Raman spectra and nonlinear optical characteristics were mea-sured to confirm the quality of the as-prepared MoS 2 -SA. By inserting the MoS 2 -SA into an EDFL, the pulsedoperation from the stable Q-switched to mode-locking regime could be achieved by simply increasing the pumppower level. The Q-switched pulse duration and repetition rate could vary from 5.18 to 3.53 μsand from 72.74to86.39 kHz, respectively. The maximum pulse energy was 74.93 nJ. After the achievement of Q-switched oper-ation, the ultrashort mode-locking pulse was obtained by further increasing the pump power. The results furtherdemonstrate the excellent saturable absorption ability of the few-layer MoS 2 at telecommunication waveband. ©2016 Society of Photo-Optical Instrumentation Engineers (SPIE) [DOI: 10.1117/1.OE.55.8.081308]

Can silicon carbide serve as a saturable absorber for passive mode-locked fiber lasers?

The study presents a novel demonstration of a passively mode-locked erbium-doped fiber laser (EDFL) that is based on a silicon carbide (SixC1−x) saturable absorber. When the C/Si composition ratio is increased to 1.83, the SixC1−x film transforms from two-photon absorption to nonlinear saturable absorption, and the corresponding value reaches −3.9 × 10−6 cm/W. The Si-rich SixC1−x film cannot mode lock the EDFL because it induced high intracavity loss through two-photon absorption. Even when a stoichiometric SiC is used, the EDFL is mode locked, similar to an EDFL operating under weak nonlinear-polarization-rotation condition. A C-rich SixC1−x film containing sp2-orbital C–C bonds with a linear absorbance of 0.172 and nonlinear absorbance of 0.04 at a 181 MW/cm2 saturation intensity demonstrates nonlinear transmittance. The C-rich SixC1−x saturable absorber successfully generates a short mode-locked EDFL pulse of 470 fs. The fluctuation of the pulse-train envelope dropps considerably from 11.6% to 0.8% when a strong saturable-absorption-induced self-amplitude modulation process occurs in the C-rich SixC1−x film.

Dual-wavelength rectangular pulse erbium-doped fiber laser based on topological insulator saturable absorber

We reported on the generation of the dual-wavelength rectangular pulse in an erbium-doped fiber laser (EDFL) with a topological insulator saturable absorber. The rectangular pulse could be stably initiated with pulse width from 13.62 to 25.16 ns and fundamental repetition rate of 3.54 MHz by properly adjusting the pump power and the polarization state. In addition, we verified that the pulse shape of the dual-wavelength rectangular pulse can be affected by the total net cavity dispersion in the fiber laser. Furthermore, by properly rotating the polarization controllers, the harmonic mode-locking operation of the dual-wavelength rectangular pulse was also obtained. The dual-wavelength rectangular pulse EDFL would benefit some potential applications, such as spectroscopy, biomedicine, and sensing research.

Passively Q-switched nanosecond erbium-doped fiber laser with MoS_2 saturable absorber

Passively Q-switched nanosecond pulsed erbium-doped fiber laser based on MoS(2) saturable absorber (SA) is experimentally demonstrated. The high quality MoS(2) SA deposited on the broadband high-reflectivity mirror with a large modulation depth of 9% was prepared by pulsed laser deposition method. By inserting the MoS(2) SA into an erbium-doped fiber laser, stable Q-switched operation can be achieved with the shortest pulse width of 660 ns, the maximum pulse energy up to 152 nJ and pulse repetition rates varying from 116 to 131 kHz. The experimental results further verify that MoS(2) possesses the potential advantage for stable Q-switched pulse generation at 1.5 μm.

All-fiber 250 MHz fundamental repetition rate pulsed laser with tilted fiber grating polarizer

We demonstrated a high fundamental repetition-rate pulsed erbium-doped fiber laser with all-fiber-integrated configuration. A novel scheme using a 45°-tilted fiber grating as the in-fiber polarizing element was employed to shorten the total cavity length and, thus, increase the fundamental repetition rate of the laser. Dissipative soliton pulses mode-locked with a fundamental repetition rate of 251.3 MHz and pulse duration of 96.7 fs have been achieved from the compact and all-fiber ring cavity laser. Additionally, passively Q-switched pulses were observed from this high fundamental repetition-rate fiber laser, which is the first report on Q-switched fiber laser using a tilted fiber grating.

Femtosecond pulse erbium-doped fiber laser by a few-layer MoS(2) saturable absorber.

We report on the generation of a femtosecond pulse in a fiber ring laser by using a polyvinyl alcohol (PVA)-based molybdenum disulfide (MoS(2)) saturable absorber (SA). With a saturable optical intensity of 34 MW/cm(2) and a modulation depth of ∼4.3%, the PVA-based MoS(2) SA had been employed with an erbium-doped fiber ring laser as a mode locker. The mode-locking operation could be achieved at a low pump threshold of 22 mW. A ∼710 fs pulse centered at 1569.5 nm wavelength with a repetition rate of 12.09 MHz had been achieved with proper cavity dispersion. With the variation of net cavity dispersion, output pulses with durations from 0.71 to 1.46 ps were obtained. The achievement of a femtosecond pulse at 1.55 μm waveband demonstrates the broadband saturable absorption of MoS(2), and also indicates that the filmy PVA-based MoS(2) SA is indeed a good candidate for an ultrafast saturable absorption device.

Concentration effect of carbon nanotube based saturable absorber on stabilizing and shortening mode-locked pulse

We comprehensively investigated the concentration effect of dispersed single-walled carbon nanotubes (SWCNTs) in polymer films for being a saturable absorber (SA) to stabilize the mode locking performance of the erbium-doped fiber laser (EDFL) pulse through the diagnosis of its nonlinear properties of SA. The measured modulation depth was from 1 to 4.5% as the thickness increased 18 to 265 microm. The full-width half-maximum (FWHM) of the stable mode-locked EDFL (MLEDFL) pulse decreased from 3.43 to 2.02 ps as the concentrations of SWCNTs SA increased 0.125 to 0.5 wt%. At constant concentration of 0.125 wt%, the similar pulse shortening effect of the MLEDFL was also observed when the FWHM decreased from 3.43 to 1.85 ps as the thickness of SWCNTs SA increased 8 to 100 microm. With an erbium-doped fiber length of 80 cm, the shortest pulse width of 1.85 ps were achieved at 1.56 microm with a repetition rate of 11.1 MHz and 0.2 mW of the output power under an output coupling ratio of 5%. An in-depth study on the stable mode-locked pulse formation employing SWCNTs SA, it is possible to fabricate the SWCNT films for use in high performance MLEDFL and utilization of many other low-cost nanodevices.

Manipulation of operation states by polarization control in an erbium-doped fiber laser with a hybrid saturable absorber

We propose an operation switchable ring-cavity erbium-doped fiber laser (EDFL) via intra-cavity polarization control. By using a semiconductor saturable absorber mirror in the EDFL cavity, stable Q-switching, Q-switched mode-locking, continuous-wave mode-locking, pulse splitting, and harmonic mode-locking pulses can be manipulated simply by detuning a polarization controller while keeping the pump power at the same level. All EDFL operation states can be obtained under the polarization angles detuning within 180 degrees. Continuous-wave mode-locking of EDFL with 800-fs pulsewidth repeated at 4 MHz has been obtained, for which the output pulse energy is 0.5 nJ and the peak power is 625 W. Interaction between solitons and the accompanied non-soliton component will lead to either pulse splitting or 5th-order harmonic mode-locking at repetition rate of 20 MHz.

Self-Steepening of Prechirped Amplified and Compressed 29-fs Fiber Laser Pulse in Large-Mode-Area Erbium-Doped Fiber Amplifier

Prechirped amplification, soliton compression, and self-pulse-steepening of a 300-fs stretch-pulse mode-locked erbium-doped fiber laser (EDFL) pulse in an ultrashort length large-mode-area erbium-doped fiber amplifier (LMA-EDFA) and large-effect-area fiber (LEAF) link are investigated. Insitu amplified compression of the single-mode-fiber prechirped EDFL pulse (broadened to 1.2 ps) is initiated in the LMA-EDFA at a pumping power of > 160 mW, which provides a 20-fold pulsewidthcompressing ratio for the incoming EDFL pulse and supports a maximum output power of > 20 dBm. With an extremely short LEAF-based fifth-order soliton stage, the amplified EDFL pulse can further be compressed down to a pulsewidth of 29 fs, which gives rise to a total pulsewidth-compressing ratio of as high as 40. The LMA-EDFA-based prechirped and amplified soliton compression leaves a small pedestal on the EDFL pulse with an energy confinement ratio of 74%, providing a 20-dB magnified pulse energy of 2.3 nJ and a 10-dB spectral linewidth of 150 nm. The self-steepening-induced blue-side spectral stretch by 1.3 THz is elucidated.

Simultaneous Switching of the ${Q}$-Value and Operation Wavelength in an Erbium-Doped Fiber Laser

We report a pulsed erbium-doped fiber laser with simultaneous switching of the laser cavity Q-value and generation wavelength. The laser generates a train of short pulses with adjacent pulses alternately being on one of two fixed wavelengths. This regime is realized at periodical modulation of physical length of overwritten fiber Bragg gratings composing the laser cavity

Sub-200-fs pulsed erbium-doped fiber laser using a carbon nanotube-polyvinylalcohol mode locker

We study the difference in mode-locked operations of different saturable absorber films made of single wall carbon nanotube-polyvinylalcohol nanocomposite. The films have different nanotube concentrations and thicknesses. For the study, a mode-locked erbium-doped fiber laser in a ring cavity configuration was constructed by setting the films in a microgap between a pair of fiber end facets. With the optimum film among those we have tested, the shortest pulses with a width of 178fs were achieved at 1.56μm with a repetition rate of 22.8MHz and an average power of 1.55mW.

Suppression of phase and supermode noise in a harmonic mode-locked erbium-doped fiber laser with a semiconductor-optical-amplifier-based high-pass filter

By operating an intracavity semiconductor-optical-amplifier- (SOA-) based high-pass filter at the nearly transparent current condition, the supermode noise (SMN), the relaxation oscillation, and the single-sideband (SSB) phase noise can be simultaneously suppressed in an actively mode-locked erbium-doped fiber laser (EDFL). The SOA at the nearly transparent condition enhances the SMN suppression ratio of the EDFL from 32 to 76 dB at the cost of the phase noise degrading from -114 to -104.2 dBc/Hz and broadening the pulse width from 36 to 61 ps. With an optical bandpass filter, the SSB phase noise and the SMN suppression ratio can be further improved to -110 dBc/Hz and 81 dB, respectively. The EDFL pulse can be further shortened to 3.1 ps with a time-bandwidth product of 0.63 after compression.

Tenth-order rational-harmonic frequency multiplication and detuning of optical pulse injection-locked erbium-doped fiber laser

The jitter and frequency-detuning dynamics of a 10-GHz rational-harmonic frequency-multiplied pulse train generated from an erbium-doped fiber laser (EDFL) is studied. The EDFL is self-feedback seeded and optically injection locked by a gain-switched laser diode (GSLD) with a pulse width and an average power of 17.6 ps and 0.2 mW, respectively, at a repetition frequency of 1 GHz. The repetition frequency of the optical pulse train can be tenth-order multiplied by a slight detuning of the repetition frequency of the GSLD to match the rational-harmonic injection-locked condition of the EDFL. As the repetition frequency is multiplied from 1 to 10 GHz, the peak power, the pulse width, and the frequency-detuning bandwidth of the injection-locked EDFL pulses decrease from 1.2 to 0.3 W, from 40 to 21 ps, and from 40 to 9 kHz, respectively. The timing jitter of the injection-locked EDFL repeated at 1 GHz remains unchanged (< 0.5 ps) within the detuning bandwidth, which inevitably increases to 1.2 ps after tenth-order multiplication.

Spectrally scanned, repetitively pulsed erbium-doped fiber laser for spectral and temporal multiplexing of fiber Bragg grating sensors.

An erbium-doped fiber laser that emits a series of spectrally scanned pulses is used to monitor an array of fiber Bragg grating (FBG) sensors. The cavity for this Fabry-Perot laser is formed by two spectrally selective reflectors: a rotating mirror-grating combination for scanning the reflectance peak wavelength and a fiber Fabry-Perot interferometer (FFPI) with a periodic reflectance spectrum. During a scan of the rotating mirror, the laser produces a set of Q-switched pulses over the 1522-1568-nm spectral range at each of the FFPI reflectance peak wavelengths. This laser is used to simultaneously demonstrate wavelength-division multiplexing of FBGs with reflectance peaks in different spectral regimes and time-division multiplexing of FBGs with overlapping spectra. The spectral location of the FBG peaks was determined to an accuracy of 1.4 pm.