Short wavelength (UV + VIS) guidance in kagomé lattice hollow core photonic crystal fibre

International audienc

Understanding origin of loss in large pitch hollow-core photonic crystal fibers and their design simplification

International audienceIt is now commonly accepted that, in large pitch hollow-core 'kagomé' lattice fibers, the loss spectrum is related to resonances of the thin silica webs in the photonic crystal cladding. Moreover, coherent scattering from successive holes' layers cannot be obtained and adding holes' layers does not decrease the loss level. In this communication, cross-comparison of experimental data and accurate numerical modeling is presented that helps demonstrate that waveguiding in large pitch hollow-core fibers arises from the antiresonance of the core surround only and does not originate from the photonic crystal cladding. The glass webs only mechanically support the core surround and are sources of extra leakage. Large pitch hollow-core fibers exhibit features of thin walled and thick walled tubular waveguides, the first one tailoring the transmission spectrum while the second one is responsible for the increased loss figure. As a consequence, an approximate calculus, based on specific features of both types of waveguides, gives the loss spectrum, in very good agreement with experimental data. Finally, a minimalist hollow-core microstructured fiber, the cladding of which consists of six thin bridges suspending the core surround, is proposed for the first time

High power Raman-converter based on H2-filled inhibited coupling HC-PCF

International audienc

Parametric four-wave mixing in strongly driven Raman molecular gas

International audienc

Raman-Kerr comb generation based on parametric wave mixing in strongly driven Raman molecular gas medium

International audienceWe report on experimental and theoretical demonstrations of an optical comb spectrum based on a combination of cascaded stimulated Raman scattering and four-wave mixing mediated by Raman-induced nonresonant Kerr-type nonlinearity. This combination enabled us to transform a conventional quasiperiodic Raman comb into a comb with a single and smaller frequency spacing. This phenomenon is achieved using a hollow-core photonic crystal fiber filled with 40 bars of deuterium and pumped with a high-power picosecond laser. The resultant comb shows more than 100 spectral lines spanning over 220 THz from 800 nm to 1710 nm, with a total output power of 7.1 W. In contrast to a pure Raman comb, a 120 THz wide portion of the spectrum exhibits denser and equally spaced spectral lines with a frequency spacing of around 1.75 THz, which is much smaller than the lowest frequency of the three excited deuterium Raman resonances. A numerical solution of the generalized nonlinear Schrödinger equation in the slowly varying envelope approximation provides very good agreement with the experimental data. The additional sidebands are explained by cascaded four-wave mixing between preexisting spectral lines, mediated by the large Raman-induced optical nonlinearity. The use of such a technique for coherent comb generation is discussed. The results show a route to the generation of optical frequency combs that combine large bandwidth and high power controllable frequency spacing

Spectral-temporal dynamics of high power Raman picosecond pulse using H2-filled Kagome HC-PCF

International audienc

Fusion splice between tapered inhibited coupling hypocycloid-core Kagome fiber and SMF

International audienc

Spectral dynamics of high power 1.8 µm laser-pulse generated by Raman conversion of a picosecond Yb-laser in hydrogen-filled Kagome HC-PCF

International audienc

Tapered hollow-core photonic crystal fiber for cascaded stimulated-Raman-scattering

International audienc

Kagome fiber based industrial laser beam delivery

International audienc