Summary: IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 43, NO. 11, NOVEMBER 2007 1083
Tapered Cavities for High-Modulation-Efficiency and
Low-Distortion Semiconductor Lasers
Farhan Rana, Christina Manolatou, and Martin F. Schubert
Abstract--We show that mode structure and cavity geometry in
multisegment semiconductor lasers can be tailored to realize high
modulation efficiencies as well as low distortion levels in directly
modulated semiconductor lasers using the gain-lever effect. Com-
pared with conventional semiconductor gain-lever lasers, the lasers
proposed here can have five times higher modulation efficiencies.
The second-order harmonic and third-order two-tone intermodu-
lation distortion levels in the proposed lasers are also significantly
lower than in conventional gain-lever lasers. We also show that, in
the lasers proposed here, unlike in conventional gain-lever lasers,
modulation bandwidths and output power levels may not be sacri-
ficed in order to obtain high modulation efficiencies.
Index Terms--Harmonic distortion, intermodulation distortion,
laser modulation, semiconductor lasers.
DIRECTLY modulated semiconductor lasers are attrac-