Optical fiber sensor for water velocity measurement in rivers and channels.

In this work, optical fiber Bragg grating sensors were used to measure water velocity and examine how it was distributed in open channels. Several types of coatings were incorporated into the design of the sensors to examine their effects on the strain that the fibers experienced as a result of the water flow. Due to their low elastic coefficient, which reduced the hysteresis, the results indicated that the aluminum- and acrylate-coated fibers had the best performance.

Effect of Linewidth on the Relative Intensity Noise in Random Distributed Feedback Raman Fiber Lasers.

We experimentally explore the relation between spectral linewidth and RIN transfer in half-open cavity random distributed feedback Raman lasers, demonstrating for the first time the possibility of adjusting the pump-to-signal RIN transfer intensity and cut-off frequency by using spectral filtering in the reflector section. We apply this approach to a 50-km laser system, operating in the C-Band, reliant on a standard single-mode fiber. We obtained a minimum bandwidth of 13 pm, which translates into a visible RIN cut-off at 800 MHz.

A Dual-Wavelength Fiber Laser Sensor with Temperature and Strain Discrimination.

This work presents a dual-wavelength C-band erbium-doped fiber laser assisted by an artificial backscatter reflector. This fiber-based reflector, inscribed by femtosecond laser direct writing, was fabricated into a single mode fiber with a length of 32 mm. The dual-wavelength laser obtained, centered at 1527.

Microdrilled tapers to enhance optical fiber lasers for sensing.

In this work, an experimental analysis of the performance of different types of quasi-randomly distributed reflectors inscribed into a single-mode fiber as a sensing mirror is presented. These artificially-controlled backscattering fiber reflectors are used in short linear cavity fiber lasers. In particular, laser emission and sensor application features are analyzed when employing optical tapered fibers, micro-drilled optical fibers and 50 μm-waist or 100 μm-waist micro-drilled tapered fibers (MDTF).

Hybrid Raman-erbium random fiber laser with a half open cavity assisted by artificially controlled backscattering fiber reflectors.

A hybrid Raman-erbium random fiber laser with a half-open cavity assisted by chirped artificially controlled backscattering fiber reflectors is presented. A combination of a 2.4 km-long dispersion compensating fiber with two highly erbium-doped fiber pieces of 5 m length were used as gain media.