RESUMEN
We study a coupled cavity laser configuration where a passively Q-switched Nd:YAG microchip laser is combined with an extended cavity, including a doped multimode fiber. For appropriate coupling levels with the extended cavity, we observed that beam self-cleaning was induced in the multimode fiber thanks to nonlinear modal coupling, leading to a quasi-single mode laser output. In the regime of beam self-cleaning, laser pulse duration was reduced from 525 to 225 ps. We also observed a Q-switched mode-locked operation, where spatial self-cleaning was accompanied by far-detuned nonlinear frequency conversion in the active multimode fiber.
RESUMEN
We experimentally demonstrate that Kerr spatial self-cleaning of a pulsed beam can be obtained in an amplifying multimode optical fiber. An input peak power of 500 W only was sufficient to produce a quasi-single-mode emission from the double-clad ytterbium doped multimode fiber (YMMF) with non-parabolic refractive index profile. We compare the self-cleaning behavior observed in the same fiber with loss and with gain. Laser gain introduces new opportunities to achieve spatial self-cleaning of light in multimode fibers at a relatively low power threshold.
RESUMEN
A sensing configuration for fluid evaporation monitoring using a suspended-core fiber tip is proposed. Strong differences between the evaporation processes of acetone and isopropyl alcohol were observed, both in terms of the signal's intensity fluctuations and total duration. In each fluid, the main signal variations were due to changes in reflectivity inside a collapsed region of the suspended-core fiber near the spliced interface with a standard single-mode fiber. After further analysis with a wider array of substances, this configuration could, in the future, be used to detect and study the evaporation of different volatile organic compounds.
RESUMEN
We report on power handling oriented design of kagome lattice hollow-core fiber and demonstrate through it for the first time nanosecond laser pulses induced spark ignition in a friendly manner. Two different core designs and transmission bands are investigated and evaluated. The energy threshold damage was measured to be in excess of the 10 mJ level and the output power density is approaching the TW/cm2 after focusing; demonstrating the outstanding ability of such fiber for high power delivery.
RESUMEN
A photonic crystal fiber based on a particular periodic arrangement of airholes and pure silica is designed for chromatic dispersion compensation. A two-concentric-core structure is obtained by introducing two different sizes of capillaries (for the airholes) and exhibits very high negative chromatic dispersion [-2200 ps/(nm km) at 1550 nm]. The variation of optogeometric parameters is also investigated to evaluate the tolerance of the fabrication. Finally, the bending influence on the modal characteristics shows that it is possible to tune the phase-matching wavelength over the C band by adjusting the diameter of the fiber.
RESUMEN
We present an erbium-doped dispersion-compensating fiber made up of two asymmetric concentric cores, inner and outer matched claddings, and erbium located in the central core only. We demonstrate a high negative chromatic dispersion value [-700 ps/(nm km) at 1568 nm], significant modification of the gain spectrum compared with that of a classic erbium-doped fiber amplifier, and 30-dB peak small-signal gain at 1535 and 1553 nm.
