Path to doubling the efficiency of mid-IR erbium lasers.

It has been experimentally shown that a Cr:ZnSe optical amplifier can be successfully used for self-amplification of the cascade Er:Y2O3 laser. This is to our best knowledge the first demonstration of an optical amplifier where both signal and pump are delivered from a single laser source. Absorption and emission spectra of the Cr:ZnSe are perfectly positioned to amplify the output of the cascade Er:Y2O3 laser, when the 1.6 µm emission of the cascade laser serves as a pump, while 2.7 µm as a signal. We have also shown that this concept is valid for any bulk or fiber cascade erbium laser.

Using a volume Bragg grating instead of a Faraday isolator in lasers incorporating stimulated Brillouin scattering wavefront reversal or beam cleanup.

A master-oscillator power-amplifier with stimulated Brillouin scattering (SBS) beam cleanup or wavefront reversal typically incorporates a Faraday isolator to outcouple the Stokes light, limiting the power scalability. Volume Bragg gratings (VBGs) have the potential for scaling to higher powers. We report here the results of tests on a VBG designed to resolve wavelengths 0.060 nm apart, corresponding to the 16 GHz frequency shift for SBS backscattering at 1064 nm in fused silica. Such an element may also find use in between stages of fiber amplifiers, for blocking the Stokes wave.