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High-power high-brightness ridge-waveguide tapered diode lasers at 14xx nm

Rippenwellenleiter Trapezdiodenlaser hoher Leistung und Brillanz bei 14xx nm
: Kallenbach, S.; Kelemen, M.T.; Aidam, R.; Lösch, R.; Kaufel, G.; Mikulla, M.; Weimann, G.


Mermelstein, C. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Novel in-plane semiconductor lasers IV : 24 - 27 January 2005, San Jose, California, USA; 2005 SPIE Photonics West Conference on Novel In-Plane Semiconductor Lasers IV
Bellingham/Wash.: SPIE, 2005 (SPIE Proceedings Series 5738)
ISBN: 0-8194-5712-4
Conference on Novel In-Plane Semiconductor Lasers <4, 2005, San Jose/Calif.>
Photonics West Conference <2005, San Jose/Calif.>
Conference Paper
Fraunhofer IAF ()
high-power diode laser; Hochleistungs-Diodenlaser; high-brightness; hohe Brillanz; tapered laser; Trapezlaser; 14xx nm; InGaAsP/InP

High-power spatially single-mode diode lasers at 1.4 - 1.5 µm wavelength are of interest as pump lasers for Raman and rare-earth doped fiber amplifiers as well as for material processing and for Light Detection and Ranging (LIDAR) at eye-safe wavelengths. A cost-efficient way to realize high-power high-brightness devices is the tapered resonator concept.
We demonstrate InGaAsP/InP based diode lasers with compressively strained quantum wells and wavelengths around 1480 nm which were grown by solid source MBE. From broad area lasers with variations in quantum well number and waveguide layer thickness, parameters for the logarithmic gain model are deduced. With their implementation in 2-dimensional BPM simulations, an optimized resonator geometry is derived. Devices employ a 500 µm ridge section followed by a 2000 µm taper section with 6° angle. Continuous-wave (cw) output powers reach more than 1.5 W. Beam quality is characterized in terms of near field and far field distribution, M2, and astigmatism. An excellent agreement is found between measurement and simulation.
For narrow-linewidth operation, devices are provided with anti-reflection coatings on both facets and spectrally stabilized with an external grating. We achieve 0.7 W single mode power and a side mode suppression ratio (SMSR) of 42 dB.
Reliability is tested in terms of facet stability and lifetime. Pulsed measurements reveal a power stability up to more than 5 MW/cm2. From cw aging tests at 1 W output power, lifetimes of about 6,000 h are extrapolated.