We present for the first time broadband operation of an optical orbital angular momentum (OAM) erbium-doped fiber amplifier lower order OAM modes based on air-hole designed and fabricated to provide significant mode splitting between |l| = 1 adjacent vector modes. Up 15.7 dB gain is obtained using a cladding pumped configuration with topological charge in operational wavelength range 1545-1600 nm.

We fabricate and characterize a germanium/thulium (Ge/Tm) co-doped silica fiber in order to enhance the gain at short wavelength edge of thulium emission band (i.e. 1620-1660 nm). The Ge/Tm doped shows an intrinsic blue-shifted absorption/emission cross-section compared aluminum/thulium (Al/Tm) fiber, which greatly improves amplification has enabled us further extend shortest towards 1600 nm. Using this glass composition, we have demonstrated both silica-based amplifier (TDFA) 1628-1655 nm...

We demonstrate a simple and power stable 1.5–10.5 µm cascaded mid-infrared 3 MHz supercontinuum fiber laser. To increase simplicity decrease cost, the design of cascade is optimized so that no thulium amplifier needed. Despite with amplifier, we high average output 86.6 mW. Stability measurements for seven days 8–9 h operation daily revealed fluctuations in standard deviation only 0.43% spectral density stability <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">...

We demonstrate highly germania doped fibers for mid-infrared supercontinuum generation. Experiments ensure a highest output power of 1.44 W broadest spectrum from 700 nm to 3200 and 6.4 800 2700 these fibers, while being pumped by broadband Erbium-Ytterbium fiber based master oscillator amplifier. The effect repetition frequency pump source length germania-doped has also been investigated. Further, conventional on silica photonic crystal source. At low power, considerable broadening 200-300...

We report an all-fiber high pulse energy ultrafast laser and amplifier operating at the short wavelength side of thulium (Tm) emission band. An in-house W-type normal dispersion Tm-doped fiber (NDTDF) exhibits a bending-induced distributed short-pass filtering effect that efficiently suppresses otherwise dominant long emission. By changing bending diameter fiber, we demonstrated tunable mode-locked with very wide range 152 nm spanning from 1740 to 1892 nm. Pulses central 1755 were able be...

Ultrashort pulse generation at the short-wave infrared (SWIR) wavelength ranges from 1.6 to 2.5μm and together with benefits of all-fiber design has transformed lasers into an essential tool for industrial, technological, scientific, environmental, medical applications. With development pumping sources fiber components, ultrafast SWIR have drawn exceptional research industrial attention over last decade, resulting in achievement comparable performance or even surpassing well-established...

A short absorption length ytterbium (Yb)-doped large-mode area (LMA) fiber is presented as a step forward to mitigate the stern problem of nonlinear scatterings in tandem pumping scheme adopted for high-power laser. The was realized by incorporating high Yb concentration core. Furthermore, replacing inherent silica cladding with Ge-doped cladding, we were able obtain low core numerical aperture (NA) and negate detrimental effect index-raising concentrations. This overcomes long-standing...

We demonstrate a high-energy and high-average power Mamyshev oscillator based on high performance large-mode-area step-index germanosilicate-cladding Yb-doped fiber. The oscillation of higher-order modes is effectively suppressed by employing appropriate intracavity spatial mode filtering, allowing significant scaling single pulse energy. laser directly generates nearly diffraction-limited beam with an average 17 W operating at the fundamental repetition rate 14.01 MHz, corresponding to...

We investigate mode-area scaling by means of supermode operation in an all-solid multicore fiber. To obtain a large-mode area (LMA), we designed and fabricated active double-clad fiber, where each ytterbium-doped core is 19 μm diameter has numerical aperture 0.067, comparable to the largest available commercial LMA fibers. The six large cores are stacked tightly ring structure enable phase locking fields operation. fiber laser performance was investigated linear cavity with external Talbot...

High concentration rare earth doped, large mode area (LMA) step-index fibers, which feature a very high cladding absorption per unit length at the pump wavelength, efficiency, and excellent beam quality, are ideal for power pulsed fiber lasers/amplifiers where effective areas short device lengths crucial in order to reduce detrimental nonlinear effects associated with peak operation. In this Letter, we realize low numerical aperture (NA) simply by employing germanium (Ge)-doped rather than...

We propose a parabolic W-type thulium-doped fiber for the 1.7 µm high-energy femtosecond pulsed laser. Despite its attractive normal dispersion, offers high gain in region thanks to distributed short-pass filtering effect. With proper dispersion management an all-fiber chirped pulse amplification (CPA) scheme, we demonstrate so far highest energy of 128.0 nJ stable 174 fs 1.7–1.8 region, which marks above order magnitude improvement while exhibiting shortest duration among fiber-based CPA...

We demonstrate a supercontinuum source with 20 dB bandwidth from ∼1 to ∼3 μm output power exceeding 6 W based on GeO2-doped silica fiber. This is the highest reported for 3 germania-doped fiber in an all-fiberized and compact size device. further spectrum spanning ∼1.7 ∼3.4 (∼10 ∼1.8 ∼3.2 μm) at low of tens milliwatts more than 50% fraction above 2400 nm, which makes this suitable several applications where broadband required avoid damage samples. Our investigations reveal unexploited...

We proposed and demonstrated mode cleaning in a high-power fiber laser by integrating an anti-resonant hollow-core (AR-HCF) into multimode cavity of ytterbium (Yb)-doped (YDF). An in-house mode-matched AR-HCF was fusion-spliced to commercial LMA-YDF, ensuring efficient fundamental coupling. The inflicts high propagation loss selectively on higher-order modes, facilitating operation. Thus, the works as spatial filter embedded reinforces preferential amplification mode. Beam quality factor...

Abstract Mid‐infrared (IR) supercontinuum (SC) lasers are important in applications such as pollution detection, stand‐off and non‐destructive testing. The performance many is limited by the noise level of laser. High typically results low sensitivities or a need for long integration times. In this paper, simple technique to reduce high soliton‐based SC sources introduced adding short piece normal dispersion fiber force spectrally distributed solitons broaden through self‐phase modulation...

We report an all-solid large-mode-area (LMA) step-index fiber offering high absorption and low core numerical aperture (NA) by introducing a highly ytterbium-doped P:Al germanium-doped cladding. The provides of ∼1200 dB/m at 976 nm with 0.07 NA, due to the raised Ge Furthermore, matched profiles P Al across are successfully obtained concentration Yb2O3 around 0.4 mol%. characteristics routinely achievable conventional modified chemical vapor deposition solution doping technique. A efficient...

The localized surface plasmon (LSP) enhancement in a gold nanoparticle is demonstrated this paper. of LSP influenced by both size and the dielectric gain medium surrounding nanoparticles. found to induce plasmonic varying degrees depending on its size, it inferred that 60 nm exhibits maximum for 532 excitation. Singularity due cancellation SP loss an infinite are studied using pump-probe Rayleigh scattering experiment. Gold nanoparticles average exhibit lowest threshold power observe...

We demonstrate a direct inscription of fiber Bragg grating (FBG) in the active cores an Yb-doped large mode area multicore (MCF). An ultrashort pulsed laser is used to inscribe FBG simultaneously all six cores. In order validate reflection and uniformity, incorporated as rear mirror oscillator setup. The MCF, which has been fabricated in-house, located hexagonal-ring shape, each with 19 µm diameter NA ∼0.067. A ∼96% was measured at center wavelength ∼1062nm for inscribed FBG. performance MCF...

We present an efficient 976 nm laser generation from ytterbium (Yb)-doped step-index multicore fiber (MCF) with six cores placed in a ring shape. Each of the has large-mode-area (LMA) and low numerical aperture (NA), which makes MCF equipped features large core-to-cladding area ratio differential bending loss for wavelength mode selection. Hence, Yb-doped benefits by simultaneously suppressing unwanted 1030 emission higher-order modes (HOMs). A is obtained short piece (88 cm) Yb MCF, good...

We report the first demonstration of Raman amplification in a fiber single Bessel-like higher order mode using multimode pump source.We amplify LP08-mode with 559-µm 2 effective area at signal wavelength 1115 nm pure-silica-core step-index fiber.A maximum 18 dB average power gain is achieved 9-m long fiber, output pulse energy 115 µJ.The source comprises pulsed 1060 ytterbium-doped amplifier V-value ~30, which matched to fiber.The depletion as averaged over pulses reaches 36.7%.The...

In this paper, gap modes assisted enhanced broadband light localization and possible absorption in a thin film silicon solar cell is presented. The existence of metal particle-surface based numerically investigated for improved absorption. About 10.2% increment compared to bare obtained at longer wavelength range observed. enhancement due the modification localized surface plasmon around nanoparticles via exciting space between nanoparticle surface.

Photodarkening in Yb-doped fibers is known to be dependent of Yb population inversion. In addition this dependence, we report that pump wavelength selection plays a significant role photodarkening dynamics. It found 976 nm source can lead more severe effects than 916 pumping at the same inversion levels. This observation consistent with various compositions. Our work reveals another determinant factor besides level and emphasizes importance high power fiber lasers amplifiers.

In this paper, we report a novel concept and methodology to fabricate high resolution periodic features using i-line laser source multiple converging lenses. This configuration reduces the number of optical elements by employing two-lens system direct beams on sample instead conventional mirror assembly that is normally associated with beam interference configurations. A simple 60° prism, 364 nm two lenses are employed implement immersion lithography achieve four interference. Square lattice...

This paper discusses and present simple wavefront interference concept, using multi facet prisms UV laser, to pattern periodic micro-features. Fabrication of square lattice features employing a biprism is illustrated. concept extended three fabricate hexagonal structures. These micro-features are expected find tunable photonic crystal applications.

In this paper, we report a methodology to fabricate high resolution periodic grating features using index prism based interferometer and i-line laser source. Features with sub-60 nm half pitch size were fabricated on resist in an immersion medium of 1.939.