Efficient broadband parametric conversion: reaching for the Mid IR

In this paper, we report recent results on the efficient generation of SWIR sources exploiting broadband wavelength conversion in silica fibers. Optimized cavity-less designs of fiber parametric amplifiers (FOPA) associated with Thulium amplification capable of high CW powers, wide tunability and modulation will be presented. We also present how parametric conversion can be extended deeper in the Mid-IR by engineering of non-silica mixing platforms

Regenerative similariton laser

Self-pulsating lasers based on cascaded reshaping and reamplification (2R) are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

Integrated Backward Second-Harmonic Generation Through Optically Induced Quasi-Phase Matching

Quasi-phase-matching for efficient backward second-harmonic generation (BSHG) requires sub-$\rm\mu$m poling periods, a non-trivial fabrication feat. For the first time, we report integrated first-order quasi-phase-matched BSHG enabled by seeded all-optical poling. The self-organized grating inscription circumvents all fabrication challenges. We compare backward and forward processes and explain how grating period influences the conversion efficiency. These results showcase unique properties of the coherent photogalvanic effect and how it can bring new nonlinear functionalities to integrated photonics

Effect of enhanced Rayleigh scattering on the random fiber laser efficiency

The effect of Rayleigh scattering enhancement in an optical fiber on the random fiber laser efficiency is investigated, and the effect of different corresponding fiber loss is also studied

Experimental and theoretical investigation of the operating principles of the Figure-9 laser, Advanced Photonics 2018 (BGPP, IPR, NP, NOMA, Sensors, Networks, SPPCom, SOF)

We present a theoretical vectorial model, validated by experimental measurements, describing the dependence of the Figure-9 laser output power, operating in continuous wave, on the coupling ratio of the directional coupler

Large second harmonic generation enhancement in SiN waveguides by all-optically induced quasi phase matching

Integrated waveguides exhibiting efficient second-order nonlinearities are crucial to obtain compact and low power optical signal processing devices. Silicon nitride (SiN) has shown second harmonic generation (SHG) capabilities in resonant structures and single-pass devices leveraging intermodal phase matching, which is defined by waveguide design. Lithium niobate allows compensating for the phase mismatch using periodically poled waveguides, however the latter are not reconfigurable and remain difficult to integrate with SiN or silicon (Si) circuits. Here we show the all-optical enhancement of SHG in SiN waveguides by more than 30 dB. We demonstrate that a Watt-level laser causes a periodic modification of the waveguide second-order susceptibility. The resulting second order nonlinear grating has a periodicity allowing for quasi phase matching (QPM) between the pump and SH mode. Moreover, changing the pump wavelength or polarization updates the period, relaxing phase matching constraints imposed by the waveguide geometry. We show that the grating is long term inscribed in the waveguides, and we estimate a second order nonlinearity of the order of 0.3 pm/V, while a maximum conversion efficiency (CE) of 1.8x10-6 W-1 cm-2 is reached

Versatile High Repetition Rate 2-μm Pulsed Source Based on Wideband Parametric Conversion

We report an all-fiber pulsed source based on parametric conversion followed by thulium amplification able to deliver picosecond pulses at a repetition rate selectable between 2 and 5 GHz, of which central wavelength can be freely selected in the 2-μm region. A very versatile Nyquist pulse shaping of the parametric pump, which allows for the electrical control of the pulse train, enables such a freedom in the repetition rate selection, as well as some control in the pulse duration. We also show that data can be embedded in the output pulse train resulting in a high-quality Gb/s return-to-zero transmitter. Such a programmable short-wave infrared laser is of high interest for sensing or nonlinear optics applications around 2000 nm that require a fine adjustment in both the spectral and temporal domains

Kerr nonlinearity and dispersion characterization of core-pumped thulium-doped fiber at 2 μm

A nonlinear coefficient of 3.6–4.1 W−1 km−1 and group velocity dispersion of −20 ps2∕km of a commercial corepumped thulium-doped fiber have been evaluated using degenerate four-wave mixing at 2 μm. The anomalous dispersion behavior of the fiber has been confirmed by linear measurements with an all-fiber Mach–Zehnder interferometer (MZI). Additionally, no pump-induced dispersion changes due to excitation of Tm3 cations have been detected. These characteristics make these fibers attractive for pulsed fiber laser applications. A nonlinear polarization rotation mode-locked laser involving nonlinear polarization evolution directly in the doped fiber is demonstrated

Erbium doped random fiber laser and fiber mixing effect

We demonstrate an active random fiber laser by directly pumping a 100 m erbium-doped fiber at 980 nm wavelength, with a fiber loop mirror forming a half-open cavity. Random lasing with competing spectral modes in the range from 1535 nm to 1560 nm is achieved, with the maximum lasing slope efficiency around 10%. We also study the effect of combining a dispersion compensated fiber with the erbium-doped fiber. The kilometers long dispersion compensated fiber reduces the random lasing threshold and increases the signal to noise ratio, while enhancing the tunability of the random laser’s spectrum range by the fiber loop mirror feedback