Distributed Bragg Reflector Tapered Diode Lasers Emitting More Than 10 W At 1154 Nm

Distributed Bragg reflector tapered diode lasers (DBR-TPL) emitting at 1154 nm are ideal light sources to be implemented into medical devices and hand-held tools for treatment in dermatology and ophthalmology at 577 nm due to their high spectral radiance enabling second harmonic generation from near infrared to yellow.In this work, we present DBR-TPLs which are able to emit more than 10 W in continuous- wave operation with a narrow spectral emission at 1154 nm and a very good beam quality providing excellent spectral radiance. The investigated DBR-TPLs are based on three different epitaxial structures with varying vertical far field angles of 35 degrees, 26 degrees, and 17 degrees. To optimize the coupling efficiency into non-linear crystals we studied DBR-TPL with a vertical far field angle of approx. 17 degrees based on an asymmetrical super large optical cavity epitaxial structure. At a pump current of 18 A these devices are able to emit more than 9 W at 25 degrees C and nearly 11 W at 10 degrees C. The spectral emission is very narrow (Delta lambda(FWHM) = 18 pm) and single mode over the entire current range. While the beam quality factor M-2 according to the 1/e(2)-level remains 1.1, the M-2 according to second order moments deteriorates when the laser is pumped with higher currents. Therefore, the power content in the central lobe increases somewhat less rapidly than the total power.