A. Klehr, S. Schwertfeger, A. Liero, Th. Hoffmann, J. Fricke, H. Wenzel, G. Erbert, and G. Tränkle

Published in:

Proc. SPIE, vol. 8277, no. 82770E (2012).

Abstract:

Mode-locked diode lasers generate reliably picosecond or even sub-picosecond optical pulses. Especially, colliding pulse mode-locked (CPM) lasers are promising sources for the generation of short optical pulses with a high repetition frequency.
We present experimental results for the generation of ps optical pulses with multi-section ridge waveguide CPM lasers. The lasers with a central emission wavelength of 1065nm consist of an odd number of 100µm long electrically separated sections. CPM operation is achieved by reverse DC biasing the central section which acts as a saturable absorber and forward DC biasing the other (gain) sections.
For a cavity length of 1.9mm, passive mode-locking is achieved for a reverse bias of -2.0V applied to the saturable absorber. The repetition frequency is about 43GHz and the pulse length is 3.3ps assuming a sech-pulse shape. The frequency comb spans 6nm assuming a dynamical range of 20dB with a frequency spacing of about 21GHz. At a cavity length of 0.9mm a frequency comb with more than 175 single frequencies over 12nm with a spacing of 45GHz is obtained. Detailed investigations of the optical pulse and frequency comb generation in dependence on cavity length, reverse absorber voltage and DC bias current will be presented.

Keywords:

Semiconductor laser, ridge waveguide laser, colliding mode locked laser, mode locking, high power optical pulse generation, frequency comb.

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