This thesis is devoted to the study of transverse modes in large-mode-area (LMA) fibers. It highlights the importance of transverse spatial-hole burning (TSHB) effect in LMA multimode fibers through experiments and simulations. The measured beam-quality factor decreases until the gain becomes saturated in an amplified spontaneous emission (ASE) source based on an Yb-doped LMA multimode fiber. A...

Here, we report a fiber-optic point-based sensor to measure temperature and weight based on correlated specklegrams induced by spatial multimode interference. The device is realized simply by splicing a multimode fiber (MMF) to a single-mode fiber (SMF) with a core offset. A series of experiments demonstrates the approximately linear relation between the correlation coefficient and variation. F...

A multimode optical fiber with a D-shaped cross section is an experimental paradigm of a wave system with chaotic ray dynamics. We show that seldom but usable modes, called scar modes, localized along some particular direction of the geometric trajectories, can be selectively excited. We report numerical simulations that demonstrate the importance of the so-called self-focal point in the scar m...

Ultrasound is a reliable non-destructive method commonly used to evaluate the state of piece wood. The effect moisture content (MC) on timber wave velocity, which different depending wood species, must be considered. MC adjustment factors are important if accurate and comparable results achieved. Thus, goal this study define model that allows obtaining factor predict standard velocity (12% (V12...

During surgery for colon cancer, monitoring of the oxygen saturation hemoglobin in tissues under study makes it possible to assess degree blood supply anastomosis areas colon. Adequate this area is decisive terms consistency and can significantly reduce risk leakage anastomosis. In work, we propose a new approach assessing based on measuring both diffuse reflectance transmittance spectra wall t...

In the fiber fuse, a pulse of high temperature travels toward the input end of the fiber, where high-power laser light is launched into the fiber. At any point along the fiber, the soliton can be ignited. The fiber core is damaged in the process so that light cannot propagate beyond the hot spot. This phenomenon is an example of a dissipative soliton that can exist only in the presence of an ex...

We report an experimental study on the backward-pumped Raman amplification of short pulses into a 20.3 km long optical fiber. demonstrate that gain and pump saturation depend pulse duration. also reveal for enough pulses, process remains linear, very high peak powers, even larger than pump, are achievable. Numerical simulations reproduce results with excellent agreement.

A Montgomery-Samelson (MS) fibering is a fibering with singularities such that the singular fibers are points. A fiber map is a map that preserves fibers and takes singular fibers to singular fibers. For MS fiberings that are the suspension of a map of a space to a point, and hence the base space is an interval, we obtain a formula for the minimum number of fixed points among all fiber maps tha...

Chip-based cavity quantum electrodynamics QED devices consisting of a self-assembled InAs quantum dot QD coupled to a high quality factor GaAs microdisk cavity are coherently probed through their optical channel using a fiber taper waveguide. We highlight one particularly important aspect of this all-fiber measurement setup, which is the accuracy to which the optical coupling level and optical ...

(Fe0 7Co0 3)1 N (or FeCoN) alloy single layers and FeCoN film sandwiched between two very thin (5 nm) permalloy layers have been synthesized by RF diode sputtering. The saturation magnetization of the as-deposited FeCoN single layers was found to be around 24.5 kG, the same as the pure Fe0 7Co0 3 alloy; and the minimum hard-axis coercivity was 5 Oe. In contrast, the sandwiched FeCoN films have ...