VCSEL arrays take on high-power pumping

Having conquered the low-power arena in the late 1990s, vertical-cavity surface-emitting-laser (VCSEL) arrays are now challenging existing technology for high-power pump applications. Princeton Optronics (Trenton, NJ) has developed 2-D VCSEL arrays that deliver as much as 220 W of continuous-wave (CW) power for pumping applications from a 5 × 5 mm chip with an emission area of 4.68 × 4.68 mm (a power density of grater than 1 kW/cm2). Minimization of the electrical resistance of the n and p distributed-Bragg-reflector mirrors and a new low-thermal-resistance (0.16°C/W) package with a thinned substrate contributed to the record high power.

In quasi-CW mode, VCSEL arrays can deliver power densities close to 2 kW/cm2. The efficiency of the 200 W array shown here exceeds 51%. Single-mode VCSEL arrays have also been fabricated and are easily coupled to fiber because of their geometry. Engineers at Princeton Optronics have coupled 80 W single-mode VCSEL arrays to 400-µm-diameter, 0.4-numerical-aperture fibers and are currently fiber-coupling higher-power arrays. Contact Chuni Ghosh at [email protected].