$400~\mathrm{\mu} \mathrm{m} $ stripe lasers for high-power fiber coupled pump modules

Abstract

We present a 940 nm quasi-continuous wave semiconductor laser designed as a building block for high-power fiber coupled pump modules. The laser comprises a $400~\mathrm{\mu} \mathrm{m} $ narrow-stripe array mounted on an aluminum nitride substrate using hard solder. The chip has been optimized for high optical power and low lateral far-field angles. Two vertical and six lateral structure variations have been investigated to determine the best achievable performance. Operating at 1 ms pulse width and a repetition rate of 10 Hz, the laser device reaches a maximum pulse power of 86 W from a $400~\mathrm{\mu} \mathrm{m} $ aperture and more than 62% maximum conversion efficiency. Low lateral far-field angles (95% power enclosed) of 11.5° and 13.5°, depending on the epitaxial design, enable efficient multimode fiber coupling. The potential for highly reliable applications has been demonstrated.

Keywords

• diode laser; high-power laser array; optical fiber coupling