Schönau am Königssee, Germany
Schönau am Königssee, Germany

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Liebich S.,University of Marburg | Zimprich M.,University of Marburg | Beyer A.,University of Marburg | Lange C.,University of Marburg | And 8 more authors.
Applied Physics Letters | Year: 2011

The lattice-matched growth of the direct band gap material Ga(NAsP) is a seminal concept for the monolithic integration of III/V laser on a silicon substrate. Here, we report on the growth, characterization, and lasing properties of Ga(NAsP)/(BGa)(AsP) multi quantum well heterostructures embedded in (BGa)P cladding layers which were deposited on an exactly oriented (001) Si substrate. Structural investigations confirm a high crystal quality without any indication for misfit or threading dislocation formation. Laser operation between 800 nm and 900 nm of these broad area device structures was achieved under optical pumping as well as electrical injection for temperatures up to 150 K. This proof of principle points to the enormous potential of Ga(NAsP) as an optical complement to Si microelectronics. © 2011 American Institute of Physics.


Scheller M.,University of Arizona | Wang T.-L.,University of Arizona | Kunert B.,NAsP III V GmbH | Stolz W.,University of Marburg | And 3 more authors.
Electronics Letters | Year: 2012

A quantum-well vertical-external-cavity surface-emitting laser in combination with a quantum-well SESAM is used to generate femtosecond pulses. The passively modelocked VECSEL operates at room temperature emitting an average output power of 5.1W at 1030nm. At a repetition rate of 1.71GHz, the 682 fs pulses are nearly transform limited. © 2012 The Institution of Engineering and Technology.


Heinen B.,University of Marburg | Zhang F.,University of Marburg | Sparenberg M.,University of Marburg | Kunert B.,NAsP III V GmbH | And 2 more authors.
IEEE Journal of Quantum Electronics | Year: 2012

Heat management is a key concern in the development of vertical-external- cavity surface-emitting lasers. Especially, high power systems are mainly limited by their heat transfer capabilities. A commonly used quantitative measure for the heat flow in such systems is the thermal resistance. So far, the thermal resistance is usually determined by evaluating the shift rates of the emission spectrum induced by varying the heat sink temperature and the input power. Yet, in multimode operation, the shift rates at the lower and the upper wavelength limit of the emission spectrum differ. In this paper, we will investigate the connection between the emission wavelength and the temperature profile inside the gain medium. We will show that the thermal resistance corresponding to the maximum pump spot temperature can only be obtained, by considering the shift rates at the long wavelength limit of the emission spectrum. Furthermore, we will show that the roll-over temperature is independent of the heat sink temperature. Based on this finding we present a novel technique, which enables the determination of the thermal resistance without the need for spectrally resolved measurements. The new technique surpasses the wavelength shift-based method both in terms of accuracy and measurement speed. © 2012 IEEE.


Kunert B.,NAsP III V GmbH | Volz K.,University of Marburg | Stolz W.,University of Marburg
ECS Transactions | Year: 2010

The novel direct band gap, dilute nitride Ga(NAsP)-material system allows for the first time the monolithic integration of a III/V laser material lattice matched to Si substrate. This lattice-matched approach offers the possibility for a high-quality, low defect density integration of a III/V-laser material potentially leading to long-term stable laser devices on Si-substrate. The broad area laser structures consist of pseudomorphically strained active Ga(NAsP)/(BGa)(AsP) multi-quantum-well heterostructures (MQWHs) embedded in thick doped (BGa)P waveguide layers, grown by a specific low-temperature metal organic vapour phase epitaxy (MOVPE) process on (001) Si-substrate. This paper will present and discuss the current status of the material and device optimization to realise electrical injection laser diodes as a basis for Si-photonics based optoelectronic integrated circuits (OEICs) with novel functionalities. ©The Electrochemical Society.


Wilcox K.G.,University of Southampton | Tropper A.C.,University of Southampton | Beere H.E.,University of Cambridge | Ritchie D.A.,University of Cambridge | And 3 more authors.
Optics Express | Year: 2013

We report a passively mode-locked vertical external cavity surface emitting laser (VECSEL) producing 400 fs pulses with 4.35 kW peak power. The average output power was 3.3 W and the VECSEL had a repetition rate of 1.67 GHz at a center wavelength of 1013 nm. A nearantiresonant, substrate-removed, 10 quantum well (QW) gain structure designed to enable femtosecond pulse operation is used. A SESAM which uses fast carrier recombination at the semiconductor surface and the optical Stark effect enables passive mode-locking. When 1 W of the VECSEL output is launched into a 2 m long photonic crystal fiber (PCF) with a 2.2 μm core, a supercontinuum spanning 175 nm, with average power 0.5 W is produced. © 2013 Optical Society of America.


Zhang F.,University of Marburg | Heinen B.,University of Marburg | Wichmann M.,University of Marburg | Moller C.,University of Marburg | And 5 more authors.
Optics Express | Year: 2014

We report on a single-frequency semiconductor disk laser which generates 23.6 W output power in continuous wave operation, at a wavelength of 1013 nm. The high output power is a result of optimizing the chip design, thermal management and the cavity configuration. By applying passive stabilization techniques, the free-running linewidth is measured to be 407 kHz for a sampling time of 1 ms, while undercutting 100 kHz in the microsecond domain. © 2014 Optical Society of America.


Gaafar M.,University of Marburg | Richter P.,University of Marburg | Keskin H.,Middle East Technical University | Moller C.,University of Marburg | And 5 more authors.
Optics Express | Year: 2014

The development of mode-locked semiconductor disk lasers received striking attention in the last 14 years and there is still a vast potential of such pulsed lasers to be explored and exploited. While for more than one decade pulsed operation was strongly linked to the employment of a saturable absorber, self-mode-locking emerged recently as an effective and novel technique in this field - giving prospect to a reduced complexity and improved cost-efficiency of such lasers. In this work, we highlight recent achievements regarding self-mode-locked semiconductor devices. It is worth to note, that although nonlinear effects in the active medium are expected to give rise to self-mode-locking, this has to be investigated with care in future experiments. However, there is a controversy whether results presented with respect to self-mode-locking truly show mode-locking. Such concerns are addressed in this work and we provide a clear evidence of mode-locking in a saturable-absorber-free device. By using a BBO crystal outside the cavity, green light originating from second-harmonic generation using the out-coupled laser beam is demonstrated. In addition, long-timespan pulse trains as well as radiofrequency-spectra measurements are presented for our sub-ps pulses at 500 MHz repetition rate which indicate the stable pulse operation of our device. Furthermore, a long-time-span autocorrelation trace is introduced which clearly shows absence of a pedestal or double pulses. Eventually, a beam-profile measurement reveals the excellent beam quality of our device with an M-square factor of less than 1.1 for both axes, showing that self-mode-locking can be achieved for the fundamental transverse mode. ©2014 Optical Society of America


Patent
Nasp Iii V Gmbh | Date: 2012-09-11

A method for producing a monolithic template comprises a Si wafer with a layer of a III/V semiconductor epitaxially applied to its surface. The III/V semiconductor has a lattice constant differing by less than 10% from that of Si. The method includes epitaxially growing a layer of a III/V semiconductor on the surface of the Si wafer at a wafer temperature from 350 to 650 C., a growth rate from 0.1 to 2 m/h, and a layer thickness from 1 to 100 nm. A layer of another III/V semiconductor, identical to or different from the previously applied III/V semiconductor, is epitaxially grown on the III/V semiconductor layer at a wafer temperature from 500 to 800 C., a growth rate from 0.1 to 10 m/h, and a layer thickness from 10 to 150 nm.


Patent
NAsP III V GmbH | Date: 2015-10-13

A monolithic integrated semiconductor structure includes: A) an Si carrier layer, B) a layer having the composition B_(x)Al_(y)Ga_(z)N_(t)P_(v), wherein x=0-0.1, y=0-1, z=0-1, t=0-0.1 and v=0.9-1, C) a relaxation layer having the composition B_(x)Al_(y)Ga_(z)In_(u)P_(v)Sb_(w), wherein x=0-0.1, y=0-1, z=0-1, u=0-1, v=0-1 and w=0-1, wherein w and/or u is on the side facing toward layer A) or B) smaller than, equal to, or bigger than on the side facing away from layer A) or B) and wherein v=1w and/or y=1uxz, and D) a group III/V, semiconductor material. The sum of the above stoichiometric indices for all group III elements and for all group V elements are each equal to one.


Patent
Nasp Iii V Gmbh | Date: 2012-07-12

A monolithic integrated semiconductor structure includes: A) an Si carrier layer, B) a layer having the composition B_(x)Al_(y)Ga_(z)N_(t)P_(v), wherein x=00.1, y=01, z=01, t=00.1 and v=0.91, C) a relaxation layer having the composition B_(x)Al_(y)Ga_(z)In_(u)P_(v)Sb_(w), wherein x=00.1, y=01, z=01, u=01, v=01 and w=01, wherein w and/or u is on the side facing toward layer A) or B) smaller than, equal to, or bigger than on the side facing away from layer A) or B) and wherein v=1w and/or y=1uxz, and D) a group III/V, semiconductor material. The sum of the above stoichiometric indices for all group III elements and for all group V elements are each equal to one.

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