We report on a Q-switched, cladding-pumped, ytterbium-doped large-mode-area fiber laser operating at 1090 nm that is capable of generating 2.3 mJ output pulse energy 500-Hz repetition rate and more than 5 W average power higher rates in high-brightness beam M2=3. Using similar with smaller core, we generated >0.5‐mJ pulses diffraction-limited beam. Our results represent threefold increase over previously published values for Q-switched lasers firmly establish as compact, multiwatt,...

We theoretically and experimentally analyze Q-switched cladding pumped ytterbium-doped fiber lasers designed for high pulse energies. compare the extractable energy from two high-energy designs: (1) single- or few-moded low-NA large mode area (LMA) fibers (2) large-core multimode fibers, which may incorporate a taper brightness enhancement. Our results show that is proportional to effective core and, therefore, LMA of comparable size give results. However, storage in mostly limited by strong...

We present a single-frequency, single-mode, plane-polarized ytterbium-doped all-fiber master oscillator power amplifier source at 1060 nm generating 264 W of continuous-wave output power. The final-stage operated with high gain 19 dB and conversion efficiency 68%. There was no evidence rollover from stimulated Brillouin scattering even the highest power, maximum limited only by available pump

We describe erbium-ytterbium co-doped fiber lasers in different free-running and tunable configurations. The were cladding-pumped by high-power multimode diode sources. compare pumping at 915 980 nm. With a laser, we obtained slope efficiencies of up to 50% with 915-nm 38% 980-nm pumping, respect absorbed pump power. reached double-ended output power 16.8 W from the laser. Thanks high rare-earth concentration small inner cladding area (possible high-brightness sources used), operating...

We report on a novel scheme to fabricate simple, cheap, and compact tunable fiber laser. The tuning is realized by splicing piece of single-mode one end an active double-clad fiber, while the other spliced 15 mm long section 105/125 multimode fiber. fluorescence signal entering into will be reproduced as single images at periodic intervals along propagation direction length chosen slightly shorter than first re-imaging point, such that coming out from mode obtained in free space, where...

Thermocavitation, the creation of a vapor bubble by heating liquid with continuous-wave laser, has been studied for wide range applications. Examples include development an actuator needle-free jet injectors, as pumping mechanism in microfluidic channels and nanoparticle synthesis. Optimal use these applications requires control over dynamics through laser power beam radius. However, influence radius on characteristics is not fully understood. Here, we present way to from optical fiber...

We demonstrate a continuous-wave (CW) single-frequency narrow-linewidth laser at 1552 nm with an output power of 83 W using master-oscillator amplifier configuration. A seed from all-fiber distributed feedback-laser linewidth 13 kHz was polarization scrambled and boosted through chain amplifiers in The last amplification stage consisted highly efficient cladding-pumped large-core erbium-ytterbium co-doped fiber which helped increase nonlinear thresholds.

We present a study of simultaneous detection curvature and strain in optical fiber. This contains micro tapered section nano section. The transmission spectrum shows interference multiple modes, the frequency modulation can be used to distinguish monitor specific physical parts fiber structure. is achieved using one component; this component an intensity with sensitivity 0.26 dB/m−1. information extracted by applying phase analysis over second spatial close 8 mrad/με. exhibits linear...

A tunable cladding-pumped ytterbium-doped fibre laser is presented. An air-clad inner cladding supported by a micro-structured silica mesh inside jacket used. measured inner-cladding NA of 0.4 to 0.5 enables efficient pump launch into 36 µm-diameter cladding. The small area tuning from 1010 1120 nm.

We demonstrate a cladding-pumped single-mode plane-polarized ytterbium-doped fiber laser generating 633 W of continuous-wave output power at 1.1 microm with 67% slope efficiency and polarization extinction ratio better than 16 dB. The is end pumped through both ends shows no evidence roll-over, even the highest power, which limited only by available pump power.

We report wide wavelength tuning in a double-clad ytterbium-doped fiber laser. The laser cavity consists of an array broadband high-reflection Bragg gratings and bulk grating as output coupler selection element. proposed configuration combines low intra-cavity loss mirrors with gratings. demonstrate > 70 nm range, limited only by the available

Transparent conducting oxides (TCOs) have recently attracted much attention in the fields of optics and photonics because their outstanding linear nonlinear optical response near-zero permittivity spectral region. The these materials can be further enhanced by optimizing material properties through fabrication. In particular, two important TCO parameters affecting strength interactions are mobility effective mass free electrons. this work, we fabricate epitaxial, highly-textured,...

We propose and demonstrate a fiber optic strain sensor based on simple splice between thin core piece of conventional single-mode fiber. Mode dispersion generates an interference reflection spectrum sensitive to temperature. The offers competitive sensitivity 2.4 pm/μɛ, good linearity (R2=0.9969), cursory repeatability analysis yielded variation. thermal studies indicate minimal cross-sensitivity (2.9 μɛ/°C). implementation without any intricate manufacturing.

Transparent Conducting Oxides (TCOs) exhibit a large and ultrafast intensity-dependent refractive index in their Epsilon-Near-Zero (ENZ) spectral region, which depends dramatically on the material properties measurement arrangement conditions. Therefore, attempts to optimize nonlinear response of ENZ TCOs usually involve extensive optical measurements. In this work, we show that significant experimental work can be avoided by carrying out an analysis material's linear response. The accounts...

Summary form only given. Cladding pumped fibre lasers are undoubtedly becoming the most attractive source of high power radiation in near IR region. The small overlap between pump and rare-earth-doped core leads to a absorption, e.g., 1 dB/m. Larger absorption is often desirable, especially if (transversally) single-mode operation can be maintained. Thus, following selective excitation fundamental mode large-core multimode fiber amplifiers was recently demonstrated short fibres. In this...

We report an ultra-widely tunable long-period holey-fiber grating, which combines the wide-range single-mode behavior and transverse strain sensitivity of holey fibers with advantages mechanically induced fiber gratings. obtain a versatile widely grating attractive transmission spectral characteristics for optical communications, fiber-based amplifiers, lasers. The shows continuous tuning range over 500 nm, more than 12 dB depth notches less 0.75 out-of-band losses, bandwidth control from 10...

An optical fiber moisture sensor is prepared by coating a 1 mm polymer with film 30 micron thick of Polyvinyl Acetate PVA. We have experimentally studied how the light transmission characteristics such coated changes as function conditions within an oil-paper insulation, to which exposed. that can be used sense present in liquid transformer oil and composite paper insulation wide range concentrations characterized. The resulting for on-line measurements electrical apparatus use under large...

The numerical analysis of inter-core crosstalk in multicore fibers (MCFs) based on a novel theoretical approach that includes stimulated Raman scattering (SRS) and four-wave mixing (FWM) nonlinearities the presence random perturbations is presented. coupled propagation equations can be employed to numerically analyze wavelength-division multiplexed systems with homogenous heterogeneous cores. Propagation ten optical channels, 200-GHz spaced, along 10 km homogeneous two-core fiber shows...

We discuss the dramatic development of high-power fiber laser technology in recent years and prospects kilowattclass single-frequency sources. describe experimental results from an ytterbium-doped fiber-based multihundred-watt single-frequency, single-mode, plane-polarized master-oscillator power amplifier (MOPA) operating at 1060 nm a similar source with 0.5 kW output power, albeit degraded beam quality (M² = 1.6) not linearly polarized. Experiments simulations aimed predicting...

Paper–oil insulation in power transformers is degraded and gradually damaged due to electrical, chemical, mechanical moisture factors. It well established from several studies that a major source of failure high voltage transformers. Measurement monitoring essential predict life operation condition for This paper presents direct optical measurement water content at immersed transformer oil inside test cell, which contains source, capillary bridge transfer the an reservoir. Optical was...

We present a numerical analysis of the thermal effect an Yb3+-doped fiber segment subjected to different temperature variation profiles, with intention determining best energy conversion efficiency. The is carried-out using pump schemes and singular profiles in fibers. study indicates that distribution, concave parabolic profile along axis, shows higher stability amplifier scheme, it therefore becomes steadier at power level. Additionally, we find for constant 20 °C, highest efficiency...