19 February 2018 Diode lasers optimized in brightness for fiber laser pumping
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Proceedings Volume 10514, High-Power Diode Laser Technology XVI; 105140F (2018) https://doi.org/10.1117/12.2290030
Event: SPIE LASE, 2018, San Francisco, California, United States
In diode laser applications for fiber laser pumping and fiber-coupled direct diode laser systems high brightness becomes essential in the last years. Fiber coupled modules benefit from continuous improvements of high-power diode lasers on chip level regarding output power, efficiency and beam characteristics resulting in record highbrightness values and increased pump power.

To gain high brightness not only output power must be increased, but also near field widths and far field angles have to be below a certain value for higher power levels because brightness is proportional to output power divided by beam quality. While fast axis far fields typically show a current independent behaviour, for broadarea lasers far-fields in the slow axis suffer from a strong current and temperature dependence, limiting the brightness and therefore their use in fibre coupled modules. These limitations can be overcome by carefully optimizing chip temperature, thermal lensing and lateral mode structure by epitaxial and lateral resonator designs and processing.

We present our latest results for InGaAs/AlGaAs broad-area single emitters with resonator lengths of 4mm emitting at 976nm and illustrate the improvements in beam quality over the last years. By optimizing the diode laser design a record value of the brightness for broad-area lasers with 4mm resonator length of 126 MW/cm2sr has been demonstrated with a maximum wall-plug efficiency of more than 70%. From these design also pump modules based on 9 mini-bars consisting of 5 emitters each have been realized with 360W pump power.
Conference Presentation
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
M. Kelemen, M. Kelemen, J. Gilly, J. Gilly, P. Friedmann, P. Friedmann, S. Hilzensauer, S. Hilzensauer, L. Ogrodowski, L. Ogrodowski, H. Kissel, H. Kissel, J. Biesenbach, J. Biesenbach, } "Diode lasers optimized in brightness for fiber laser pumping", Proc. SPIE 10514, High-Power Diode Laser Technology XVI, 105140F (19 February 2018); doi: 10.1117/12.2290030; https://doi.org/10.1117/12.2290030

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