Spectral Linewidth vs. Front Facet Reflectivity of 780 nm DFB Diode Lasers at High Optical Output Power

T.-P. Nguyen1, H. Wenzel2, O. Brox2, F. Bugge2, P. Ressel2, M. Schiemangk2, A. Wicht2, T.Q. Tien3 and G. Tränkle2

Published in:

Appl. Sci., vol. 8, no. 7, pp. 1104 (2018).

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The influence of the front facet reflectivity on the spectral linewidth of high power DFB (distributed feedback) diode lasers emitting at 780 nm has been investigated theoretically and experimentally. Characterization of lasers at various front facet reflections showed substantial reduction of the linewidth. This behavior is in reasonable agreement with simulation results. A minimum linewidth of 8 kHz was achieved at an output power of 85 mW with the laser featuring a front facet reflectivity of 30%. The device with a front facet reflectivity of 5% reached the same linewidth value at an output power of 290 mW.

1 School of Engineering Physics, Hanoi University of Science and Technology, No. 1 Dai Co Viet, Hai Ba Trung, Hanoi, Vietnam
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
3 Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam


semiconductor laser; narrow linewidth; high power diode laser; front facet reflectivity.