High-power extended cavity narrow linewidth laser

We present a compact extended cavity laser (ECL) system based on a high-power laser diode with reduced linewidth and stabilized to the rubidium D₁ line at the 794.74 nm. The laser system was derived from an arrangement designed for optical pumping of Rb and production of hyperpolarized gasses. We concentrated on the ECL system optimization - linewidth narrowing effects with the broad-area power laser diode. We show that the intensity of optical feedback in the ECL laser influences linewidth and output power and it is possible to find an optimum value for the highest power spectral density and eventually adjust the linewidth over wide range. The emission linewidth was reduced approximately 10 times with only half of the total optical power loss. The ECL system is controlled by electronic servo-loop for laser frequency stabilization.