Broadband laser light sources in the mid-infrared region attract enormous interest due to plethora of applications they are enabling, including multispecies trace gas detection, free-space communications, and infrared countermeasures. Key progress supercontinuum generation has been wide availability fiber-based near-infrared bulk-optic pump suitably engineered nonlinear media capable supporting high-brightness supercontinua. A large proportion system complexity relates source itself with...

We present a novel method to fabricate low bend loss femtosecond-laser written waveguides that exploits the differential thermal stabilities of laser induced refractive index modifications. The technique consists two-step process; first involves fabricating large multimode waveguides, while second step post-annealing process, which erases outer ring profile, enabling single mode operation in C-band. By using this procedure we report with sharp bends (down 16.6 mm radius) and high (80%)...

We report a 790 nm pumped, Tm³⁺ doped ZBLAN glass buried waveguide laser that produces 47 mW at 1880 nm, with 50% internal slope efficiency and an M² of 1.7. The cladding is defined by two overlapping rings created femtosecond direct-writing the glass, which results in formation tubular depressed-index-cladding structure, resonator external dielectric mirrors. This is, to best our knowledge, most efficient host via writing.

The recent demonstrations of ultrafast mid-infrared fiber lasers emitting sub-picosecond pulses at 2.8 μm have created an exciting potential for a range applications including frequency combs and materials processing. So far, this new class laser has been based on the I11/24-I13/24 transition in erbium-doped fluoride fibers, which lies directly region high water vapor absorption. This absorption limited achievable bandwidth, pulse duration, peak power poses serious problem transmission free...

Rare-earth-doped fiber lasers are emerging as promising high-power mid-infrared sources for the 2.6–3.0 μm and 3.3–3.8 regions based on erbium holmium ions. The intermediate wavelength range, however, remains vastly underserved, despite prospects important manufacturing defense applications. Here, we demonstrate potential of dysprosium-doped to solve this problem, with a simple in-band pumped grating-stabilized linear cavity generating up 1.06 W at 3.15 μm. A slope efficiency 73% respect...

In the two decades since first extra-solar planet was discovered, detection and characterization of planets has become one key endeavours in all modern science. Recently, direct techniques such as interferometry or coronagraphy have received growing attention because they reveal population exoplanets inaccessible to Doppler transit techniques, moreover allow faint signal from itself be investigated. Next-generation stellar interferometers are increasingly incorporating photonic technologies...

We compare and contrast novel techniques for the fabrication of chirped broadband fiber Bragg gratings by ultrafast laser inscription. These methods enable inscription with flexible period profiles thus tailored reflection dispersion characteristics in non-photosensitive optical fibers. Up to 19.5 cm long a spectral bandwidth up 30 nm were fabricated grating was characterized. A maximum group delay almost 2 ns obtained linearly either normal or anomalous velocity dispersion, demonstrating...

Fiber Bragg gratings inscribed with a femtosecond laser using the point-by-point (PbP) technique have polarization dependent grating strength (PDGS) and exhibit birefringence. In this paper we quantify dependence of these two properties on ellipticity, position in core size micro-voids at center each refractive index modulation. We demonstrate that effective modal for type II written PbP method must be lower than pristine fiber, first time associate an axis such long elliptically-shaped...

Fibre Bragg gratings inscribed with the point-by-point method using a Ti-sapphire femtosecond laser operating at 800 nm are shown to display strong increasing attenuation towards shorter wavelengths large and spectrally sharp recovery observed below 400 nm.The origin of this loss is be Mie scattering, in transmission results from wavelength dependent scattering within numerical aperture core.The permanent losses these Type II have implications for high temperature sensors fibre lasers.

We report performance characteristics of a thulium doped ZBLAN waveguide laser that supports the largest fundamental modes reported in rare-earth planar (to best our knowledge). The high mode quality waveguides up to 45 um diameter (~1075 μm(2) mode-field area) is validated by measured beam M(2)~1.1 ± 0.1. Benefits these large mode-areas are demonstrated achieving 1.9 kW peak-power output Q-switched pulses. 1.89 μm free-running cw produces 205 mW and achieves 67% internal slope efficiency...

Nanosheets of bismuth telluride (Bi 2 Te 3 ), a topological insulator material that exhibits broadband saturable absorption due to its non‐trivial Dirac‐cone like energy structure, are utilized generate short pulses from Tm:ZBLAN waveguide lasers. By depositing multiple layers carefully prepared Bi solution onto glass substrate, the modulation depth and saturation intensity fabricated devices can be controlled optimized. This approach enables realization absorbers feature 13% 997 kW/cm . For...

A wide range of saturable absorbers composed novel low-dimensional nanomaterials were fabricated, and their linear nonlinear optical properties characterized. Furthermore, suitability for ultrashort-pulse generation in waveguide laser operating at a wavelength 2 microns was demonstrated passively q-switched mode-locked operation achieved with all absorbers. The material systems that studied this work include nanosheet-based graphene, carbon nanotubes, black phosphorus, transition-metal...

We propose and demonstrate a simple route to few-optical-cycle pulse generation from mid-infrared fiber laser through nonlinear compression of pulses holmium-doped oscillator using short length chalcogenide grating pair. Pulses the with 265-fs duration at 2.86 μm are spectrally broadened self-phase modulation in step-index As2S3 141-nm bandwidth then re-compressed 70 fs (7.3 optical cycles). These shortest system date, we note that our is compact, robust, uses only commercially available...

We report on the power scaling to 103 W of a 1.1 μm continuous-wave Yb3+-doped silica fiber laser incorporating point-by-point (PbP) fiber-Bragg grating inscribed directly into active core using 800 nm femtosecond pulses. The spectrum exhibited narrow linewidth that broadened 260 pm at W. output was frequency doubled an 11 mm long periodically poled MgO:LiNbO3 crystal generate 2.1 green with internal conversion efficiency 10% high and 0.81%/W low power.

The combination of ultrafast laser inscription and engineered soft glasses is enabling a new class photonic devices offering long wavelength transparency, high nonlinearity, optical gain. However, this field research also possesses its own unique set fabrication challenges, which range from the predictable, such as self‐focusing effects, material stress, damage to unexpected, photo‐induced index changes different sign. In article, we review many challenges surrounding laser‐written...

We report the first Ho3+ doped waveguide laser, which was realized by femtosecond direct-writing of a depressed cladding structure into ZBLAN glass. Tm3+ sensitizing allows 9 mm long gain medium to be conveniently pumped at 790 nm, achieving an optical-to-optical slope efficiency 20% and threshold 20 mW. The potentially widely tunable laser produces up 76 mW 2052 nm also operates shorter wavelengths near 1880 1978 for certain cavity configurations.

We report the development of a widely tunable all-fiber mid-infrared laser system based on mechanically robust fiber Bragg grating (FBG) which was inscribed through polymer coating Ho3+-Pr3+ co-doped double clad ZBLAN fluoride by focusing femtosecond pulses into core without use phase mask. By applying mechanical tension and compression to FBG while pumping with an 1150 nm diode, continuous wave (CW) tuning range 37 nm, centered at 2870 demonstrated up 0.29 W output power. These results pave...

We report the direct femtosecond laser inscription of type-I fiber Bragg gratings (FBGs) into core soft-glass ZBLAN fibers. investigate and compare various fabrication methods such as single pass (line by line), double pass, stacking (plane plane) to create highest reflectivity FBGs (99.98%) for mid-infrared (mid-IR) applications. In addition, we experimentally demonstrate how parameters that influence coupling coefficient, i.e., refractive index modulation overlap factor, can be controlled...

We report on the fabrication of, to best of our knowledge, first highly reflective fiber Bragg gratings for 4 µm wavelength range. A second-order grating with a coupling coefficient (κ) 230m-1, losses <0.25dB/cm, and bandwidth approximately 3 nm was inscribed into core passive indium fluoride (InF3) using femtosecond (fs) laser. Thermal annealing this at temperature 150°C 90 min resulted in enhancement κ 275m-1. Further, we show that InF3 fibers respond very differently irradiation fs laser...

We demonstrate operation of a mid-infrared dysprosium-doped fiber laser with emission at 3388 nm, representing the longest wavelength yet achieved from this class laser, to best our knowledge. Oscillation far removed <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">D</mml:mi> </mml:mrow> <mml:msup> mathvariant="normal">y</mml:mi> <mml:mn>3</mml:mn> <mml:mo>+</mml:mo> </mml:msup> </mml:math> gain peak...

We report the high-efficiency operation of a 3.05 µm dysprosium-doped fluoroindate glass fiber laser that is in-band pumped at 2.83 using an erbium-doped fluorozirconate laser. The demonstrated slope efficiency free-running 82% represents approximately 90% Stokes limit; maximum output power 0.36 W, highest for laser, was recorded. Narrow-linewidth wavelength stabilization 3.2 achieved by utilizing first-reported, to best our knowledge, high-reflectivity Bragg grating inscribed in Dy3+-doped...

Abstract A general picture of refractive index change mechanisms in glass modified by a femtosecond laser has proven elusive. In this paper, Raman microscopy was used conjunction with near‐field profilometry to analyse the structure borosilicate (Schott BK7) and determine mechanism observed change. For pulse repetition rate 1 kHz, it determined that due an elevated population non‐bridging oxygen atoms, resulting more ionic bonds forming within network increasing molar refractivity glass. 5.1...

Fluorozirconate glasses, such as ZBLAN (ZrF 4 -BaF 2 -LaF 3 -AlF -NaF), have a high infrared transparency and large rare-earth solubility, which makes them an attractive platform for highly efficient compact mid-IR waveguide lasers.We investigate the structural changes within glass network induced by repetition rate femtosecond laser pulses reveal origin of observed decrease in refractive index using Raman microscopy.The pulse train causes local melting followed rapid quenching network.This...

The femtosecond laser direct write technique was used to fabricate mid-infrared compatible waveguide couplers into Suprasil 3001, a fused silica glass with an OH content of as low ≤1 ppm. Smooth positive step-index change multi-scan waveguides were produced high index contrast 1 × 10−2, measured directly using quadriwave lateral shearing interferometry. Waveguides annealed at 400 °C for 15 h and found be highly stable, only &amp;lt;5% reduction in change. Brillouin microscopy...