Mode-locked Tm-doped Fiber Laser Research Articles

Modeling the Broadband Mid-Infrared Dispersion Compensator Based on ZBLAN Microfiber

The waveguide dispersion profiles of (ZrF4–BaF2– LaF3 – AlF3 – NaF) (ZBLAN) microfiber in the mid-infrared (mid-IR) regime have been investigated numerically. The results show that ZBLAN microfiber has large normal dispersion for wavelength ranging from 2 to 5 $\mu \text{m}$ by tailoring the fiber geometry. Moreover, the Tm-doped mode-locked fiber laser has been modeled with the ZBLAN microfiber as the dispersion compensator, and the ultrafast pulse around 2 $\mu \text{m}$ can be generated. The results confirmed the availability of the dispersion compensator for mid-IR ultrafast photonics.

Ultra-broadband dissipative soliton and noise-like pulse generation from a normal dispersion mode-locked Tm-doped all-fiber laser.

We report generation of ultra-broadband dissipative solitons and noise-like pulses from a simple, fully fiberized mode-locked Tm-doped fiber laser. The oscillator operates in the normal net dispersion regime and is mode-locked via nonlinear polarization evolution. Depending on the cavity dispersion, the laser was capable of generating 60 nm or 100 nm broad dissipative solitons. These are the broadest spectra generated from a normal dispersion mode-locked Tm-doped fiber laser so far. The same oscillator might also operate in the noise-like pulse regime with extremely broad emission spectra (over 300 nm), which also significantly outperforms the previous reports.

260 fs and 1 nJ pulse generation from a compact, mode-locked Tm-doped fiber laser.

We report on generation of 260 fs-short pulses with energy of 1.1 nJ from a fully fiberized, monolithic Tm-doped fiber laser system. The design comprises a simple, graphene-based ultrafast oscillator and an integrated all-fiber chirped pulse amplifier (CPA). The system generates 110 mW of average power at 100.25 MHz repetition rate and central wavelength of 1968 nm. This is, to our knowledge, the highest pulse energy generated from a fully fiberized sub-300 fs Tm-doped laser, without the necessity of using grating-based dispersion compensation. Such compact, robust and cost-effective system might serve as a seed source for nonlinear frequency conversion or mid-infrared supercontinuum generation.

Switchable multi-wavelength Tm-doped mode-locked fiber laser.

We propose and demonstrate for the first time a switchable tri-wavelength Tm-doped ultra-fast fiber laser based on nonlinear polarization evolution (NPE) technique. The NPE effect induces wavelength-dependent loss in the cavity that changes the homogeneous broadening of the effective gain to become inhomogeneous. This inhomogeneous effective gain spectral profile enables the multi-wavelength mode locking. Binary control of three bits can be realized by controlling the polarization in the compact fiber ring cavity. Such switchable laser has potential applications in optical signal processing and communication.

Tunable and switchable dual-wavelength Tm-doped mode-locked fiber laser by nonlinear polarization evolution.

We propose and demonstrate a tunable and switchable dual-wavelength ultra-fast Tm-doped fiber laser. The tunability is based on nonlinear polarization evolution (NPE) technique in a passively mode-locked laser cavity. The NPE effect induces wavelength-dependent loss in the cavity to effectively alleviate mode competition and enables the multiwavelength mode locking. The laser exhibits tunable dual-wavelength mode locking over a wide range from 1852 to 1886 nm. The system has compact structure and both the wavelength tuning and switching capabilities can be realized by controlling the polarization in the fiber ring cavity.

Self-mode-locked 2 μm Tm3+-doped double-clad fiber laser with a simple linear cavity

We demonstrate the self-mode-locking operation of a thulium (Tm)-doped fiber laser (TDFL) with a simple linear cavity. Since the laser cavity does not include any specific mode-locker, we experimentally investigate and analyze the self-mode-locking mechanism. The mode-locking operation is attributed to the combination of the self-phase modulation effect and the weak saturable absorption of the high-concentration Tm-doped fiber. The mode-locked TDFL operates at a central wavelength of 1985.5nm with the 3dB spectral linewidth of 0.18nm. The self-mode-locking generates a large pulse energy of 32.7nJ with a pulsed repetition rate of 2.05MHz and is stable with a radio-frequency signal-to-noise ratio of more than 54dB. To the best of our knowledge, it is the first demonstration of a 2μm Tm-doped fiber laser mode-locked by such technique.

Pulse dynamics controlled by saturable absorber in a dispersion-managed normal dispersion Tm-doped mode-locked fiber laser

Based on the coupled Ginzburg-Landu equation, we numerically investigate the pulse dynamics in a dispersion-managed normal dispersion Tm-doped mode-locked fiber laser. The influences of the modulation depth and saturation power of saturable absorber on the pulse dynamics are presented. The simulation results show that these parameters are crucial to achieve high pulse energy and high pulse peak power pulsed laser near 2-\mu m wavelength.

Efficient, high peak power Tm:YLF laser

We demonstrate efficient generation of diode pumped, passively cooled Tm:YLF laser end-pumped by 25-W fiber coupled laser diode. Over 5 W of output power was achieved for 25-W pumping laser and for elongated 120-mm cavity. For the free-running and Q-switching regimes the output spectrum was centered at 1908-nm with linewidth less than 7 nm. In the experiments on active Q-switching up to 5.5 mJ of output energy was demonstrated with pulse duration of 11 ns, corresponding to ~0.5 MW of peak power. Full Text: PDF References Jabczynski, J.K., Gorajek, L., "High repetition rate, high peak power, diode pumped Tm:YLF laser," Laser Phys. Lett. 6 (2), 109-112 (2009) CrossRef Sha, J.J., Shen, D.Y., Zhao, T., Yan, X.F., "High power and highly efficient operation of a Tm:YAG laser in-band pumped at 1617 nm", Laser Phys. Lett. 10, 075801 (2013) CrossRef Guillemet, S., "High pulse energy sub-nanosecond Tm-doped fiber laser". Proc. SPIE 8237, Fiber Lasers IX: Technology, Systems, and Applications, 82373V (2012) CrossRef Swiderski, J., Maciejewska, M., Kwiatkowski, J. and Mamajek, M., "An all-fiber, resonantly pumped, gain-switched, 2 ?m Tm-doped silica fiber laser", Laser Phys. Lett. 10, 015107 (2013). CrossRef Swiderski, J. and Michalska, M., "Generation of self-mode-locked resembling pulses in a fast gain-switched thulium-doped fiber laser," Opt. Lett. 38, 1624-1626 (2013) CrossRef Kwiatkowski, J., Jabczynski, J. K., Gorajek, L., Zendzian, W., Jelinkowa, H., Sulc, J., Nemec, M., Koranda, P., "Resonantly pumped tunable Ho:YAG laser", Laser Phys. Lett. 6 (7), 531-534 (2009) CrossRef Kwiatkowski, J., Jabczynski, J.K., Zendzian, W., Swiderski J., Gorajek, L. and Galecki, L., "Resonantly pumped acousto-optically Q-switched hybrid Ho:YAG laser", Laser Phys. Lett. 8 (4), 281-285 (2011) CrossRef Gallian, A., Fedorov, V. V., "Hotpressed ceramic Cr2+:ZnSe gain-switched laser", Opt. Express 14, 11694?11701 (2006) CrossRef Creeden, D., Ketteridge, P., "Mid-infrared ZnGeP2 parametric oscillator directly pumped by a pulsed 2 ?m Tm-doped fiber laser," Opt. Lett. 33, 315-317 (2008) CrossRef Swiderski, J. and Maciejewska, M., "Watt-level, all-fiber supercontinuum source based on telecom-grade fiber components", Appl. Phys. B 109, 177-181 (2012) CrossRef Swiderski, J. and Michalska, M., "Mid-infrared supercontinuum generation in a single-mode thulium-doped fiber amplifier", Laser Phys. Lett. 10, 035105 (2013) CrossRef Swiderski, J., Michalska, M. and Maze, G., "Mid-IR supercontinuum generation in a ZBLAN fiber pumped by a gain-switched mode-locked Tm-doped fiber laser and amplifier system," Opt. Express 21, 7851-7857 (2013) CrossRef

Mode-locked 2-μm wavelength fiber laser using a graphene-saturable absorber

Soliton-like pulses with a 1984-nm center wavelength are pro- duced from a Tm-doped mode-locked fiber laser. The linear cavity has a graphene saturable absorber mirror at one end and a fiber Bragg grating as the output coupler. The laser operates without dispersion compensa- tion, and the repetition rate was tuned from 20 to 5 MHz by the addition of SMF-28 fiber. The dry transfer process used to place the graphene on a mirror could be extended to any optical substrate. This enables integration of graphene with optics such as an optical window coated with a graphene filter or a graphene-saturable absorber placed directly on a semiconductor laser facet. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attri- bution of the original publication, including its DOI. (DOI: 10.1117/1.OE.52.7.076101)

Mid-IR supercontinuum generation in a ZBLAN fiber pumped by a gain-switched mode-locked Tm-doped fiber laser and amplifier system

We demonstrate a novel method of mid-infrared (mid-IR) supercontinuum (SC) generation with the use of a 2 µm gain-switched self-mode-locked thulium-doped fiber laser. SC radiation ranging from ~1.9 to 3.8 µm wavelength, generated in a single-mode ZBLAN fiber with a zero-dispersion wavelength (ZDW) shifted to ~1.9 µm, is reported. An average output power of 0.74 W with 0.27 W at wavelengths longer than 2.4 µm was measured. It is, to the best of our knowledge, the first report on such an approach to generate a mid-IR SC in optical fibers.

Time-domain ABCD matrix analysis of passively mode-locked Tm-doped fiber laser

Basing on time-domain ABCD matrix formalism, the characteristics of pulsewidth and chirp of an ultra-short pulse Tm-doped fiber laser based on graphene saturable absorber are analyzed theoretically. The expressions of pulsewidth and chirp are derived, and the influences of optical fiber dispersion and optical fiber nonlinearity are investigated. Numerical results show that the pulse width is shorter in the negative dispersion region, and the pulse width decreases with the increase of self-phase modulation effect. The pulse width is always larger in positive dispersion region than that in negative dispersion region. An ultra-short pulse at ∼2μm with pulsewidth below 100fs can be achieved.