Output Characteristics Of Fiber Laser Research Articles

Fiber gratings matching and output characteristics of fiber laser

In order to improve the output power and processing quality in industrial applications, it is important to optimize the output characteristics of the high-power fiber lasers. The slope efficiency, backward leaking power and stimulated Raman scattering are key issues in high-power fiber laser design. The parameters matching the fiber gratings, which are the critical components, have a direct influence on the whole fiber laser system. In this paper, the parameters matching the fiber gratings in fiber lasers are investigated. Firstly, the origin of slope efficiency, backward leaking power and stimulated Raman scattering are analyzed in theory. Then the influences on output characteristics of fiber lasers comprised of the output coupler gratings, which have different bandwidths and reflectivities, are experimentally studied. Finally, the optimized parameters and matching principle of fiber gratings in high-power fiber laser are obtained , thus providing an alternative method to improve the output characteristics of high-power continuous wave fiber laser.

Sensitivity enhancement in erbium-doped fiber laser intra-cavity absorption sensor

The sensitivity of an erbium-doped fiber laser intra-cavity loss sensor is investigated theoretically and experimentally. The laser rate equations are modified to analyze the output characteristics of fiber laser under different pump powers and intra-cavity losses. Theoretical analysis shows that high sensitivity can be achieved when pump power is reduced to close to threshold value. The general trends of experimental results agree with the theoretical predictions.

Effects of Wavelength Dependent Birefringence inside a Fiber Cavity on the Fiber Laser Output Characteristics with a Nonlinear Amplifying Loop Mirror

We have theoretically analyzed and experimentally observed the effects of wavelength dependent birefringence inside a laser cavity on the output characteristics of fiber lasers with a figure eight geometry. The spectral and polarization characteristics of fiber lasers are found to be very susceptible to the resultant birefringence composed of the intrinsically existing wavelength dependent birefringence and the externally induced birefringences inside the fiber. For the variation of twist-induced birefringence inside the nonlinear amplifying loop mirror, the laser output power and center wave-length of continuous wave lasers change periodically, but the polarization characteristics remains nearly unchanged. The changes of the birefringence inside the linear loop has little effect on the spectral characteristics but changes the polarization properties such as the polarization direction.