Svyatoslav Kharitonov

High-power parametric conversion from near-infrared to short-wave infrared

We report the design of an all-fiber continuous wave Short-Wave Infrared source capable to output up to 700 mW of power at 1940 nm. The source is tunable over wavelength intervals comprised between 1850 nm and 2070 nm depending on its configuration. The output can be single or multimode while the optical signal to noise ratio ranges from 25 and 40 dB. The architecture is based on the integrated association of a fiber optical parametric amplifier and a Thulium doped fiber amplifier.

Characterization and modeling of microstructured chalcogenide fibers for efficient mid-infrared wavelength conversion

We experimentally demonstrate wavelength conversion in the 2 µm region by four-wave mixing in an AsSe and a GeAsSe chalcogenide photonic crystal fibers. A maximum conversion efficiency of -25.4 dB is measured for 112 mW of coupled continuous wave pump in a 27 cm long fiber. We estimate the dispersion parameters and the nonlinear refractive indexes of the chalcogenide PCFs, establishing a good agreement with the values expected from simulations. The different fiber geometries and glass compositions are compared in terms of performance, showing that GeAsSe is a more suited candidate for nonlinear optics at 2 µm. Building from the fitted parameters we then propose a new tapered GeAsSe PCF geometry to tailor the waveguide dispersion and lower the zero dispersion wavelength (ZDW) closer to the 2 µm pump wavelength. Numerical simulations shows that the new design allows both an increased conversion efficiency and bandwidth, and the generation of idler waves further in the mid-IR regions, by tuning the pump wavelength in the vicinity of the fiber ZDW.

Data transmission in long-range dielectric-loaded surface plasmon polariton waveguides

We demonstrate the data transmission of 10 Gbit/s on-off keying modulated 1550 nm signal through a long-range dielectric-loaded surface plasmon polariton waveguide structure with negligible signal degradation. In the experiment the bit error rate penalties do not exceed 0.6 dB over the 15 nm wavelength range and received optical power between -7 and 3 dBm.

Linearly chirped mid-infrared supercontinuum in all-normal-dispersion chalcogenide photonic crystal fibers

We demonstrate all-normal dispersion supercontinuum generation in chalcogenide photonic crystal fibers pumped at 2070-2080 nm with a femtosecond fiber laser. At 2.9 kW peak power, the generated supercontinuum has a 3 dB bandwidth of 27.6 THz and -20 dB bandwidth of 75.5 THz. We experimentally investigated the supercontinuum evolution inside our sample fiber at various peak powers and fiber lengths and study the impact of fiber water absorption on the generated supercontinuum spectrum. Multiple tests with fiber length- ranging from 0.34 to 10 cm-provide insight on pulse evolution along fiber length. Our simulations, which utilizes the generalized nonlinear Schrodinger equation model, match perfectly the experiments for all tested pump powers and fiber lengths, and confirm that the output pulse has a linear chirp, allowing linear pulse compression.

All-fiber dissipative soliton resonance mode-locked figure-9 thulium-doped fiber laser

Dissipative soliton resonance (DSR) fiber mode-locked lasers (MLL) are attracting a steadily growing interest over the recent years, due to their ability to generate relatively long (ns-scale), strongly chirped and large energy pulses directly inside a main oscillator. Thulium-doped fiber (TDF) DSR MLLs, optionally enhanced with amplification and compression stages, are in high demand in various application areas in 2-μm spectral region, like surgery, LIDAR and remote sensing, microscopy, etc. Figure-8 (F8) TDF laser, emitting 20 nJ pulses from net-normal-dispersion cavity, was demonstrated [1]. More advanced total-anomalous-dispersion F8 cavity, involving double-clad (DC) TDF and two-stage post-amplification, was used to obtain a pulse energy of 66 μJ [2]. The nonlinear amplifiying loop mirror (NALM) was exploited in both experiments as a mode-locking element. Being mainly fiber-based, above-mentioned configurations include some inherently free-space components, such as isolators, which have lower damage threshold, comparing to all-fiber elements. In this paper, we demonstrate the first truly all-fiber figure-9 (F9) DSR TDF laser that emits nanosecond pulses with energies up to 400 nJ, which is to the best of our knowledge a record value of the energies, extracted directly from the DSR oscillator at 2 μm.

All-optically induced quasi phase matching in SiN waveguides for second harmonic generation enhancement

We report more than 30dB second harmonic generation enhancement in SiN waveguide by all-optical writing of a persistent χ(2) grating. Phase matching peaks are observed for different writing wavelengths.

Large second harmonic generation enhancement in Si 3 N 4 waveguides by all-optically induced quasi-phase-matching

Efficient second harmonic generation in integrated platforms is usually achieved by resonant structures, intermodal phase-matching or quasi-phase matching by periodically poling ferroelectric waveguides. However, in all these structures, it is impossible to reconfigure the phase-matching condition in an all-optical way. Here, we demonstrate that a Watt-level laser causes a periodic modification of the second-order susceptibility in a silicon nitride waveguide, allowing for quasi-phase-matching between the pump and second harmonic modes for arbitrary wavelengths inside the erbium band. The grating is long-term inscribed, and leads to a second harmonic generation enhancement of more than 30 dB. We estimate a χ(2) on the order of 0.3 pm/V, with a maximum conversion efficiency of 0.05% W−1. We explain the observed phenomenon with the coherent photogalvanic effect model, which correctly agrees with the retrieved experimental parameters.Phase-matching and quasi-phase-matching in periodically poled ferroelectrics ensure efficient harmonic generation, but only statically. Here, Billat et al. demonstrate all-optically reconfigurable second harmonic generation by inscribing a stable grating in CMOS-compatible nonlinear waveguides.

Broadband Dispersion Characterization of Chalcogenide Tapered Photonic Crystal Fiber

Group-velocity dispersion of birefringent GeAsSe tapered PCF is directly measured over 1900-2300nm range using all-fiber Mach-Zehnder interferometer. We experimentally prove that zero-dispersion wavelength of chalcogenide PCFs can be shifted to thulium/holmium doped silica emission band.

Broadband characterization of ZBLAN fiber for short-wave infrared applications using all-fiber interferometer

Group-velocity dispersion, third-order dispersion and propagation losses of 14m normal dispersion ZBLAN fiber are directly and continuously measured over 1500-2100nm range using all-fiber Mach-Zehnder interferometer. The fiber is then used for dispersion compensation at 2μm.

Generation of high-brightness spectrally flat supercontinuum in 1900-2450 nm range inside a small core thulium-doped fiber amplifier

We demonstrate the generation of high-brightness supercontinuum inside thulium-doped fiber amplifier in 1950-2450nm spectral range with 1.7W output power and 32% slope efficiency, seeded by tunable 2000nm mode-locked laser and assisted by 3H4-3H5/3F4-3H6 thulium transitions