Linewidth narrowing and wavelength stabilization of high-power laser diode array by use of volume Bragg grating

The characteristics of the LDA operating in the steady state are analyzed. The carrier density, oscillating frequency, photon density compared to those in free-running state operating in the in-phase mode are analyzed. In this paper, linewidth narrowing and wavelength stabilization of a high-power laser diode array are obtained by using an external cavity consisting of Volume Bragg Grating (VBG) with the reflectivity of 15 %. At the driven current up to 40 A, an output power of 28 W is obtained with the linewidth down to 0.3 nm, which corresponds to the efficiency of 93.3% compared to the output power in free-running LDA. The intensity of the external-cavity LDA is improved by a factor of approximately 3.3, and the wavelength is stabilized at 808nm determined by the VBG. This kind of laser diode array has potential applications in pumping solid-state lasers, medical treatment and gas sensing.