The sensor optimization is devoted to the study of the improvement of the sensor performance (sensitivity, operating interval) as a function of the radius of curvature of the micro-mirrors and the core diameter of the optical fibres. When the mode field diameter of the single mode fibre is smaller, the size of the waist image should have the same value (at a temperature or pressure value) to have a maximum coupling efficiency. During the fluctuation of T or P, the waist size image, which depends on the bend radius of the micro-mirror, scans the mode field diameter of the SMF beyond the Rayleigth range. As a result, the variation in the intensity of the reflected light is relatively faster. So, the slope of the coupling efficiency curve is quite steep. The sensitivity is improved but the range of temperature or pressure variation is shorter. Conversely, if the sizes are relatively large (SMF core as well as waist image), the scanning area is longer, so the sensitivity decreases, but the dynamic range is enlarged. This imposes a choice of detection. The main results and the structure of the sensor will be presented.
In recent years, the rare earth ions and primarily Er played a crucial role in the development of the technology of optical telecommunications. The Emission of erbium ions at 1.53 microns is important for optical telecommunications because this emission corresponds to minimum mitigation of silica fibers which used as purpose to transport information. At first, we study the evolution of the signal powers and the pump powers along the propagation in the optical fiber amplifier Erbium doped. In addition, we study the variation of Erbium ions concentration for different spectroscopic parameters such as signal strength with (0, 1μW, 1mW) and the power of the pump going up 200 mW.
A fiber laser is a laser whose gain medium is a doped fiber, although lasers whose cavity is made wholly of fibers have
also been called fiber lasers. The gain media in a fiber laser is usually fiber doped with rare-earth ions, such as erbium
(Er), neodymium (Nd), ytterbium (Yb), thulium (Tm), or praseodymium (Pr), which is doped into the core of the optical
fiber, similar to those used to transmit telecommunications signals. Fiber lasers find many applications in materials
processing, including cutting, welding, drilling, and marking metal. To maximize their market penetration, it is necessary
to increase their output power. In this work, we present a detailed study based on the numerical simulation using
MATLAB, of one of the principal characteristics of a fiber laser doped with rare earth ions and transition ion. The gain
depends on several parameters such as the length of the doped fiber, the density, the pump power, noise, etc.). The used
program resolves the state equations in this context together with those governing the light propagation phenomena. The
developed code can also be used to study the dynamic operating modes of a doped fiber laser.
Concave cone fabricated by chemical etching process similar to previous technique used to make fiber tips (convex cone) is presented. Typically, optical fibers are etched in a fluorhydric (HF) solution with a thin layer of oil floating on top of the HF. The present investigation shows that concave cone etched fiber (CCEF) can be obtained by following the beginning of etching process. Comprehensive measurements of the dependence of the width and height of taper angle of the concave cone are plotted. The results of this investigation have led to an optimum approach for fiber cores alignment that is suitable for use in connecting fibers for efficient coupling between single-mode fibers.