High Temperature Operation of 1060-nm High-Brightness Photonic Band Crystal Lasers With Very Low Astigmatism

Thermally stable and nearly astigmatism free 1060-nm high-brightness photonic band crystal lasers are presented. A thick asymmetric waveguide with an optimized doping profile is employed. The prominent mode-discrimination property of the structure yields highly stable laser beam characteristics (i.e., beam quality factor M $^2$ , astigmatism) regardless of operating current and temperatures up to 80 $^\circ$ C. Ridge waveguide lasers with 6- $\mu$ m ridge width and 2.64-mm cavity length provide 1.8-W output power and 61-MW $\cdot$ cm $^{-2}$ $\cdot$ sr $^{-1}$ brightness in continuous-wave mode at $T$ = 20  $^\circ$ C. Full width at half maximum beam divergence remains below 11 $^\circ$ in lateral and 15 $^\circ$ in vertical direction up to the highest output power. Output power decreases with increasing heat sink temperature, however, a still large value of 1.3 W is achieved at $T = 80\;^\circ$ C. Excellent beam quality with both lateral and vertical M $^2 1.9 is obtained across the full investigated operating range up to 80 $^\circ$ C heat sink temperature. Astigmatism varies only between 0.4 to 2  $\mu$ m at all operating conditions.