Nd-doped Fiber Research Articles

Thermoluminescence Properties of Optical Fibers Doped with RE<sup>+3</sup> (RE=Sm, Nd) Ions Subjected to X-Ray Irradiation

This paper describes the thermoluminescence properties of RE+3(RE=Nd, Sm) doped optical fiber SiO2 prepared by CorActive company in Canada. The samples were exposed to 6 MV X-ray irradiation at dose ranging from 0.5 to 4 Gy at hospital Sultan Ismail, Johor Bahru, Malaysia using the LINAC accelerator. After exposure and a certain delay of 12 h to get uniform control of thermal fading, the optical fiber TL yield was readout using a TL reader. The optical fiber demonstrated a linear TL response versus of the absorbed dose. The linearity increases with the increasing dose while in the case of Sm-doped optical fiber; the response is comparatively smaller than Nd-doped optical fiber. Also, the glow curve of RE+3 ions doped optical fiber is compared with the undoped fibers. The results exhibit that the glow curve peaks are shifted to higher temperature due to rare-earth doping. As the results indicate the TL response strongly depends on the doping type of materials. All these TL characteristics are proposing this commercial optical fiber very decisive TL material.

Thermoluminescence characteristics of Nd-doped SiO2 optical fibers irradiated with the 60Co gamma rays

Thermoluminescence (TL) properties (radiation sensitivity, dose response, signal fading) of Nd-doped SiO2 optical fibers irradiated with 1.25MeV photons to 1–50Gy were studied. The peak of the glow curve is around 190°C regardless of the dose. The dose response is linear up to 50Gy. The radiation sensitivity is 219nCmg−1Gy−1. The fiber can be a potential candidate for photon radiotherapy dosimetry due to its high radiation sensitivity, linear dose response in a wide range, slow fading, and high spatial resolution due to the small size of the fiber.

Core-pumped femtosecond Nd:fiber laser at 910 and 935 nm.

We report a core-pumped all-normal dispersion mode-locked Nd-doped fiber laser at 910 and 935nm. The pulse is compressed to 198fs, and the pulse energy is 1.3nJ. The slope efficiency is more than 14%. This laser is tested as the optical source for the two-photon fluorescence imaging of pollen.

Short-length fiber laser oscillation in 4-mm Nd-doped silica fiber fabricated by zeolite method

We demonstrated laser oscillation in an only 4-mm Nd-doped silica fiber, which is 10 times shorter than the previously reported one. This fiber-core glass, which was fabricated by the zeolite method, contained 1.25wt% of Nd2O3. The laser output power was observed to be 3.1mW at 1060nm, and the laser threshold power and slope efficiency were 7.7mW and 8.9%, respectively. Nd-doped silica fiber can produce high-repetition and extremely compact short-pulse laser devices and will also be applied to optical integrated circuits with environmental toughness in practical use.

Mode-locked Nd-doped fiber laser at 930 nm

We report on a passively mode-locked neodymium-doped oscillator featuring a W-type fiber operating at 930 nm. Two different laser configurations with and without dispersion management are investigated to generate high-energy similaritons. Chirped pulses with 2.2 nJ energy that can be compressed to 126 fs are generated in the dispersion-managed cavity. The ANDI-fiber laser delivers parabolic pulses with 5.2 ps duration that can be compressed to 146 fs.

Analysis of thermal effects in end-diode-pumped, Q-switched Nd:YVO4 laser

We present a laboratory model of a Q-switched Nd:YVO 4 laser with thermal effects compensation dedicated as a laser head for marking devices. Theoretical analysis on thermal effects were performed and resonator parameters were optimized. For 10 kHz repetition rate we obtained about 0.25 mJ of pulse energy corresponding to about 45 kW of peak power with slope efficiency 14%. M 2 parameter was 1.6. Full Text: PDF References J. E. Geusic, H. M. Marcos, L. G. Van Uitert, "Laser oscillations in nd-doped yttrium aluminum, yttrium gallium and gadolinium garnets", Applied Physics Letters 4 (10), (1964) CrossRef L. Gorajek, L. Galecki, "Tunable, gain switched Ti3+:Al2O3 laser pumped by intracavity frequency doubled Nd3+:YLF laser", Photonics Letters of Poland 1, No 3, 136-138 (2009) CrossRef W. Zendzian, J. K. Jabczynski, P. Wachulak, J. Kwiatkowski, "High-repetition-rate, intracavity-pumped KTP OPO at 1572 nm", Appl. Phys. B 80, 329-332 (2005) CrossRef J. Swiderski, A. Zajac, P. Konieczny, M. Skorczakowski, "Numerical model of a Q-switched double-clad fiber laser", Opt. Express 12, 3554-3559 (2004) CrossRef J. Swiderski, A. Zajac, P. Konieczny, M. Skorczakowski, "Q-switched Nd-doped double-clad fiber laser", Opto-Electronics Review, vol. 13, no. 3, 29-33, 2005 DirectLink

20 W continuous-wave cladding-pumped Nd-doped fiber laser at 910 nm

We demonstrate a double-clad fiber laser operating at 910 nm with a record power of 20 W. Laser emission on the three-level scheme is enabled by the combination of a small inner cladding-to-core diameter ratio and a high brightness pump source at 808 nm. A laser conversion efficiency as high as 44% was achieved in CW operating regime by using resonant fiber Bragg reflectors at 910 nm that prevent the lasing at the 1060 nm competing wavelength. Furthermore, in a master oscillator power-amplifier scheme, an amplified power of 14.8 W was achieved at 914 nm in the same fiber.

Amplification at 1400–1450 nm of the Large-Core Nd-Doped Fiber by White LED Pumping

A novel cost-effective fiber amplifier operating over 1400-1450 nm is developed based on pumping of a large-core Nd-doped fiber with a high-power white light-emitting diode (LED). An optical gain of 6 dB at 1400 nm is obtained by simultaneously exciting the multiple absorption bands in the visible wavelength of the Nd-doped fiber.

Local-cooled watt-level Nd-doped phosphate single-mode fiber laser

Efficient and stable continuous-wave (CW) laser operation at 1053 nm in a Nd-doped phosphate single-mode fiber (Nd:PSMF) has been demonstrated experimentally. The fiber laser consisted of a 21 cm Nd:PSMF placed in a F-P cavity formed by high reflector butt-coupled to coupling end of the fiber and Fresnel reflection of the other end facet. An output power of 1.42 W and a slope efficiency of 34.1% (18.4%) with respect to absorbed pump power (incident pump power) were obtained with 808 nm diode pumping. An increment as much as 9.7 and 15.0% in slope efficiency of the input coupling efficiency and the output power, respectively, were obtained by using a local-cooling design provided by watered sealing the coupling point. The repeatable results indicate that the design, featuring fluid sealing the coupling point of the fiber laser, which was capable of offering an effective alleviation of thermal effects and an elevation of the quality of the laser cavity, could be expected to be a convenient and effective scheme to improve the performance characteristics of the non-silica fiber lasers and the high power fiber lasers, generally in free-space coupling configuration.

Review on recent progress on Yb-doped fiber laser in a variety of oscillation spectral ranges

We present review on recent progress on high power Yb-doped fiber laser in a variety of oscillation spectral ranges. According to Kurkov (Laser Phys. Lett. 2006), the oscillation spectral range of YDFLs can be divided into three bands: convenient (C-band), short (S-band), and long (L-band). For the C-band YDFL, tandem-pumped high power radiation by using 1018 nm fiber laser or 1030 nm thin-disk laser is reviewed. For the S-band YDFL, three mainly technical solutions, i.e., special designed fiber, the employment of photonic crystal fiber (PCF), and tandem pumping using 930 nm Nd-doped fiber laser are presented. For the L-band laser, active heating or self-heating the active fiber can help the long-wavelength oscillation. Fiber Raman laser or amplifier can also boost the power of L-band YDFL up. Some discussions and prospective predictions are proposed at the end of this paper.

Laser emission from a solar-pumped fiber

We report the realization of a solar-pumped fiber laser (SPFL) using a double-clad (a center core/ an inner clad working also as optical waveguide/ an outer clad) Nd-doped fluoride optical fiber as a laser medium. With a compact off-axis parabolic mirror of 5 cm in aperture diameter, the natural sunlight is concentrated by a factor 10⁴, and introduced partly into the core of the fiber and partly into the inner clad in which the light is guided in some distance and transferred to the core after all. We have obtained clear laser spectrum characteristics with approximately 0.01 nm full-width-half-maximum of the laser line at the peak wavelength of 1053.7 nm, a low-lasing threshold of 49.1 mW, a slope efficiency of 6.6%, and a total efficiency of 1.76%. Further optimization of the medium properties, optical cavity, and concentration technique will yield higher efficiency and lower threshold.

Positive Gain Observation in a Nd-Doped Active Fiber Pumped by Low-Concentrated Solar-Like Xenon Lamp

Positive Gain Observation in a Nd-Doped Active Fiber Pumped by Low-Concentrated Solar-Like Xenon Lamp

Positive Gain Observation in a Nd-Doped Active Fiber Pumped by Low-Concentrated Solar-Like Xenon Lamp

Neodymium-doped silica glass fiber is pumped by a Xe arc lamp as a simulated solar light. The fiber is immersed in rhodamine 6G solution to enhance the photon flux at the 588 nm absorption band of the Nd3+. The chamber that contains the active fiber and dye solution is made of a pair of reflectors. The bottom reflector is highly reflective over the entire visible spectrum, while the top reflector is a short-pass dichroic mirror whose cutoff wavelength is set at 580 nm. As a result, the dye fluorescence of the absorption band is confined by the multiple reflections, like a “greenhouse effect”. The expected confinement factor as a function of the angular-dependent reflectivity of the reflectors is discussed. The highest gain observed is 1.0 ×10-2 m-1 when the lamp light intensity is 2.7 W/cm2.

Efficient Generation of Watt-Level Output From Short-Length Nd-Doped Phosphate Fiber Lasers

We report experimental results on high-power heavily Nd-doped phosphate continuous-wave (CW) fiber lasers of very short length. The optimum fiber laser with a length of 26 cm exhibited a maximum output power of as much as 2.87 W and a slope efficiency of 44.7% with respect to absorbed pump power at 795 nm. Up to 1-W laser was also obtained from a 6-cm-short active fiber. The fiber lasers were demonstrated at 1053 nm with a linewidth of 1.6 nm, and showed no evidence of roll-over even at highest output power. The output powers were stable and limited only by available pump power.

Phase locking of a compact Nd-doped phosphate multicore fiber laser

Two compact fiber lasers based on the gain medium of Nd-doped phosphate glass multicore fiber (MCF), of length no more than 10 cm, have been demonstrated experimentally for the first time. A stable phase-locked laser beam at 1055 nm emitted from a three-core fiber that is 8.5 cm in length has been achieved, with a maximum output power of 20 mW. The properties of similar seven-core fiber laser also have been investigated.

Laser oscillation in 5-cm Nd-doped silica fiber fabricated by zeolite method

We have demonstrated a laser oscillation in the highest concentration and the shortest Nd-doped silica fiber, an only 5-cm multimode Nd-doped silica fiber. This fiber-core glass was fabricated by the zeolite method, and the glass contained 1.25 wt.% of Nd 2O 3, which is 10 times higher than previously reported Nd-doped silica fiber. The laser output power was 10 mW at 1062 nm, and the threshold power and slope efficiency of the laser oscillation was 1.39 W and 2.4%, respectively.

Generation of picosecond blue light pulses at 464 nm by frequency doubling an Nd-doped fiber based Master Oscillator Power Amplifier

We demonstrate 308 mW of single-mode laser emission at 464 nm from a frequency doubled picosecond fiber based Master Oscillator Power Amplifier (MOPA). The laser system consisted of a gain-switched and spectrally narrowed Fabry-Perot laser diode emitting at 928 nm, which was amplified in a two-stage amplifier based on W-type double-clad Nd-doped fibers. Output pulses with a duration of 90 ps at a repetition rate of 41 MHz were frequency-doubled in a periodically poled MgO-doped Congruent Lithium Niobate. A conversion efficiency of 14.8% was achieved in single-pass configuration.

Q-switching of a fiber laser with a single crystal photo-elastic modulator

A study of using a single crystal photo-elastic modulator for active Q-switching of a fiber laser is presented. The modulator, which oscillates in a longitudinal eigenmode, was realized with LiTaO(3). This induces due to the photo-elastic effect a modulated artificial birefringence which modulates the polarization of passing light. When used together with a polarizer inside a laser cavity the laser photon life time is strongly modulated and the laser may start to emit laser pulses. We realized this with a fiber laser based on a 5m long double clad Nd-doped fiber. The pulse repetition frequency was 400 kHz and the pulse duration 300ns.

Transparent and inclusion-free RE 1−xLa xVO 4 (RE=Gd, Y) single crystal fibers grown by LHPG technique

We describe in this work the growth of pure and Nd-doped transparent fibers of RE 1− x La x VO 4 (RE=Gd, Y and x = 0.2 , 0.4 and 1.0) by the laser heated pedestal growth technique. The fibers obtained were in the range of 400–700 μm in diameter and up to 40 mm in length. Our crystalline fibers were free of black phases and microscopic inclusions. Temperature measurements on the molten zone surface showed that the liquid temperature suddenly dropped approximately 200 °C. This decrease in the liquid temperature is here associated with an self-adjustment of the melt composition during the fiber growth. Crystallographic data shows that the obtained fibers ( x = 0.2 and 0.4) belong to the I4 1/amd symmetry, with the exception of LaVO 4 ( x = 1.0 ), which crystallized with P2 1/n symmetry. Optical absorption and lifetime measurements on Nd-doped fibers showed the same good optical properties as the Nd:YVO 4 bulk crystals, with larger spectral linewidths which are desired for diode laser pumping.

Yb-, Er—Yb-, and Nd-doped fibre lasers based on multi-element first cladding fibres

Single-mode cw Yb-, Er—Yb, and Nd-doped fibre lasers are fabricated by using fibres of a complicated structure (a few silica fibres in optical contact with each other are surrounded by a polymer jacket). Such a structure allows the coupling of radiation from several pump sources into one active fibre, providing an increase in the output power of the fibre laser. The Yb-doped fibre lasers with the output power above 50 W and efficiency ∼65% and the 1.608-μm Er—Yb-doped fibre laser pumped to the absorption band of Yb are fabricated and studied. The Nd-doped fibre lasers based on such fibres and emitting at 0.92 and 1.06 μm are manufactured for the first time.