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

Abstract

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.

Ultrabright Polarization-Entangled Photon Pair Source for Frequency-Multiplexed Quantum Communication in Free-Space

“…VBGs are an excellent candidate for wavelength demultiplexing in polarization-based quantum communication channels including: high diffraction efficiency (> 99% achievable [19]); low absorption loss [19,20]; suitability for application in space environment (under radiation, temperature fluctuations and etc.) [21]; lifespan [22]; wavelength range (∼ 350 − 2500 nm) and versatile spectral bandwidth [23]; and polarization insensitivity [24]. Furthermore, we determine the optimal source emission rate for the entire system taking into account the increased quantum bit error rate due to higher order pair emission at high pump powers, as well as the detectors characteristic temporal response function and the electronic coincidence window.…”