Series in Quantum Electronics
edited by
Henry Baltes, Peter Günter, Ursula Keller,
Fritz K. Kneubühl †, Walter Lukosz,
Hans Melchior, Markus W. Sigrist
Vol. 47
Aude-Reine Bellancourt
MODELOCKING OF SEMICONDUCTOR VERTICAL
EMITTERS: FROM VECSEL TO MIXSEL
1st
edition 2009. XXII, 120
pages; € 64,00.
ISBN 978-3-86628-242-1
Thanks to
their vertical emission and external cavity, optically pumped VECSELs (vertical
external cavity surface-emitting lasers) offer excellent single transverse mode
beam quality at higher powers than any other semiconductor lasers. The output power can be simply scaled up by
increasing the pump spot diameter, enabling output powers as high as 20 W
so far, in fundamental transverse mode (M2<1.1). Furthermore, the semiconductor gain offers a
great flexibility in design and makes it possible to address a large wavelength
range from visible to infrared.
The low gain
saturation of VECSELs is moreover favorable for
passive modelocking with semiconductor saturable absorber mirrors (SESAMs) and reduces Q-switching
instability issues. SESAM-VECSEL modelocking have been demonstrated with high power up to
2.08 W at 4 GHz, as well as high repetition rates up to 50 GHz.
In this
thesis, we present a detailed study on modelocked
VECSELs, which resulted in a new type of integrated modelocked
VECSEL: the MIXSEL (modelocked integrated external-cavity surface
emitting laser). The development of
quantum dot based SESAMs (QD-SESAMs) with low saturation fluence
achieved through a resonant field enhancement in the absorber was a key
achievement in the demonstration of the MIXSEL as it enables modelocking with same mode sizes on the gain and absorber
sections. With the MIXSEL, where a saturable absorber is integrated in the gain structure, modelocking can be achieved from a simple straight
cavity. 185 mW
average power was demon-strated
at 2.9 GHz with 31.6 ps pulses. We discuss
the saturable absorber requirements and challenges
for integration in the MIXSEL and for power scaling and pulse shortening.
Finally, we
investigated the QD absorber properties for a better understanding and
improvement of the MIXSEL design. This
study resulted in the demon-stration of antiresonant multiple-layer QD-SESAMs, which are very
promising for MIXSEL integration. Antiresonant designs will improve the growth tolerance and
lower MIXSEL dispersion, which is especially important for short pulse
generation and high repetition rates.
About the Author:
Aude-Reine Bellancourt
received her engineer degree in physics and optics from the ‘Institut d’Optique Graduate
School’ in 2005. She joined the
Institute for Quantum Electronics at ETH Zurich in the same year. Her research focused on development of
semiconductor vertical external cavity surface-emitting lasers (VECSELs) as
well as passive modelocking of these lasers with
SESAMs for ultrafast lasers with multi-GHz repetition rates. She has written and co-authored more than 30
scientific journal articles and conference contributions.
Keywords: vertical external-cavity surface-emitting laser (VECSEL),
semiconductor saturable absorber mirror (SESAM),
modelocked integrated
external-cavity surface emitting laser
(MIXSEL), thin disk semiconductor laser, passive modelocking, optically pumped semiconductor lasers
Direkt bestellen
bei / to order directly from:
Hartung-Gorre Verlag / D-78465
Konstanz / Germany
Telefon: +49
(0) 7533 97227 Telefax: +49 (0) 7533
97228
http://www.hartung-gorre.de eMail: verlag@hartung-gorre.de