Simulation of the generation of high-power pulses in the GHz range with three-section DBR lasers
K.-H. Hasler, H. Wenzel, A. Klehr, G. Erbert
Ferdinand-Braun-Institut für Höchstfrequenztechnik, Albert-Einstein-Straße 11, D-12489 Berlin, Germany
Published in:
IEE Proc.-Optoelectron., Vol. 149, No. 4, August 2002, pp. 152-160
© 2002 The IEE.
Abstract:
The dynamical behaviour of three-section distributed Bragg reflected (DBR) lasers
containing an active gain section and passive phase-shift and Bragg grating sections was studied
and modelled by numerically solving the travelling wave equations and a rate equation for the
carrier density. By changing the parameters determining the optical gain or absorption, respectively,
in the phase section a switching behaviour, hysteresis phenomena and self-sustained
pulsations were obtained. By injecting small current pulses through the phase section, high power
optical pulses with small spectral width and repetition rates in the GHz range were generated.
Experimentally, this was achieved by a selective heating of the phase section and by modulating
the current injected into the phase section. In contrast to DBR lasers emitting at 1.3 µm and
1.55 µm, in the DBR lasers under investigation with an emission wavelength of 1.06 µm the active
layer extends over all sections. Thus by the heating the interband absorption in the active layer of
the phase section is strongly increased, while owing to the current pulses the absorption is rapidly
reduced. Thus, giant light pulses are emitted which have a small spectral width owing to the
wavelength selectivity of the Bragg grating.
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