Spectral Stabilization of Laser Diodes by External Bragg Resonator

Volume Bragg laser VOBLA with feedback produced by a reflective photo-thermo-refractive volume Bragg grating is used for narrowing spectral width and angular divergence of laser diodes. High-efficient, single mode and spectral width of 60 pm at power of 800 mW are demonstrated from 35 and 100 m-stripe laser. The problem of high-brightness, high-efficient semiconductor laser sources with stable narrow emission spectra is important for different kinds of applications. Various constructions of external resonators for laser diodes LD were proposed and investigated, but up to now no successful commercial product resulted from those researches. First of all, no diffraction limited single lobe emission was obtained for external cavity semiconductor lasers under high pumping current 1-5. The other reason restraining external cavity applications is an additional number of optical elements, which should be aligned with very high accuracy. Application of novel photo-thermo-refractive PTR glass Volume Bragg Laser VOBLA concept to semiconductor lasers allows simplifying an external cavity construction and obtaining narrow spectrum and near-diffraction limited divergence laser beam with no losses of original efficiency of LD.