M. Monerie

Modeling of pair-induced quenching in erbium-doped silicate fibers

It is shown that in low-concentration erbium-doped silicate fibers (below 1000 p.p.m.), a residual absorption at 980 nm cannot be saturated. Usual models for upconversion of Er/sup 3+/ cannot match this behavior nor explain a fluorescence lifetime independent of pump power and erbium concentration. A phenomenon, the pair induced quenching (PIQ), that is compatible with the previous experimental results is exhibited. The influence of erbium and aluminum concentration on the ion pair proportion is shown. >

Three ways to implement interfacial techniques: application to measurements of chromatic dispersion, birefringence, and nonlinear susceptibilities

Depending on the spectal width of the source illuminating an interferometer, measurement procedures can utilize either the whole interferogram, or only the fringe envelope, or only the fringe quick oscillations. With an ultraband spectrum source, a simplified adaptation of the methods of Fourier transform spectroscopy yields the variations of the test-fiber propagation constant over the whole wavelength-interval of the source. Chromatic dispersion can then be computed from a single interferogram. With narrower spectrum sources, only the fringe envelopes are utilized and yield measurements of mode delay, with application to chromatic and polarization mode dispersion. In this case, however, interferograms at several wavelengths are necessary. With even narrower spectrum sources, the fringe quick oscillations provide measurements of phase shifts, related to changes in the mode propagation constant, when outside perturbations are applied to the test fiber. A direct method for measuring the third-order nonlinear susceptibilities is discussed. In this case the outside perturbation is an intense pump laser field. >

Programmable fiber grating based wavelength demultiplexer

Summary form only given. In conclusion, we have demonstrated that piezoactuated gratings can be combined to build active demultiplexers or wavelengths routers. With minor modifications, this device can operate as a programmable add and drop multiplexer.

Fundamental mode propagation characteristics of depressed-inner-cladding single-mode fibers

Depressed inner cladding (DIC) single-mode fibers potentially have ultimate low loss and very interesting dispersion properties in the 1.5-1.7-μm region. Depending on their profile geometry they can exhibit a nonzero fundamental mode cutoff.1 We report here experimental evidence of this phenomenon.