The mid-infrared molecular fingerprint region has gained great interest in the last decade thanks to development of on-chip semiconductor lasers and mid-IR optical fibers. For integrated-optic devices and optical sensors based on interferometric techniques, versatile and easy handling devices can be required. In this context, low-loss single-mode chalcogenide microstructured optical fibers (MOF) which presents an antireflection coating have been elaborated in order to be connected to a Distributed Feedback Quantum Quantum Cascade Laser (DFB-QCL). In addition, another original design of a chalcogenide MOF has been also realized in order to obtained high birefringence properties that can permit to maintain the polarization of the QCL at the output of the fiber. Finally, the fiber properties have been evaluated using a DFB-QCL emitting at 7.4 µm and the polarization maintaining of the chalcogenide fiber has been demonstrated.
The combination between a DFB-QCL with such non-conventional fibers has led to the development of single-mode fibered Mid IR lasers.
 J. Troles, L. Brilland, C. Caillaud, J.-L. Adam, Advanced Device Materials, 3 (2017) 7-13.
 C. Caillaud, C. Gilles, L. Provino, L. Brilland, T. Jouan, S. Ferre, M. Carras, M. Brun, D. Mechin, J.-L. Adam, J. Troles, , Optics Express, 24 (2016) 7977-7986.
The design and realization of high-quality bandpass optical filters are often very difficult tasks due to the strong correlation of the optical index of dielectric thin films to their final thickness, as observed in many industrial deposition processes. We report on the optimization of complex optical filters in the visible and NIR spectral ranges as realized by ion beam-assisted electron beam deposition of silica and titanium oxide multilayers. We show that this process always leads to amorphous films prior to thermal annealing. On the contrary, the optical dispersion of TiO2 nanolayers is highly dependent on their thickness, while this dependence vanishes for layers thicker than 100 nm. We demonstrate that accounting for this nonlinear dependence of the optical index is both very important and necessary in order to obtain high-quality optical filters.