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Guther R.,Ferdinand - Braun - Institute
Optics Letters

The recently calculated high diffraction efficiencies for TE- and TM-polarized light (perfect blaze) for echelette gratings are explained by four-wave interference, which is formed as a double periodical pattern in the cross section of the grating plane. The blazed grating profile should match this interference pattern for a single reference light wavelength. The recently published data are the special case of a general design. The prognoses of the model are connected with large grating constants in comparison with the light wavelength, where short grating constants need comparison with numerical methods. © 2012 Optical Society of America. Source

Rumiantsev A.,TU Brandenburg | Doerner R.,Ferdinand - Braun - Institute
IEEE Microwave Magazine

Today, radio-frequency (RF) wafer probes play an important role in almost every step of the RF products lifecycle: from technology development, model parameter extraction, design verification, and debug to small-scale and final production test. By using RF probes, it became possible to measure true characteristics of the RF components at the wafer level. One of the earliest measurement results obtained using RF probes were presented in, demonstrating usable device data up to 4 GHz. The probes used in this experiment were very different from today's tools. While it was possible to remove the impact of relatively large series inductance of a contact wire tip by the calibration procedure, the authors of observed large changes in the radiation impedance of the wire tip when the wafer chuck was moved. Source

Wenzel H.,Ferdinand - Braun - Institute
IEEE Journal on Selected Topics in Quantum Electronics

The aim of this paper is to review some of the models and solution techniques used in the simulation of high-power semiconductor lasers and to address open questions. We discuss some of the peculiarities in the description of the optical field of wide-aperture lasers. As an example, the role of the substrate as a competing waveguide in GaAs-based lasers is studied. The governing equations for the investigation of modal instabilities and filamentation effects are presented and the impact of the thermal-lensing effect on the spatiotemporal behavior of the optical field is demonstrated. We reveal the factors that limit the output power at very high injection currents based on a numerical solution of the thermodynamic based drift-diffusion equations and elucidate the role of longitudinal spatial hole burning. © 1995-2012 IEEE. Source

Klopp P.,Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy | Griebner U.,Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy | Zorn M.,Ferdinand - Braun - Institute | Zorn M.,JENOPTIK Diode Laboratory GmbH | Weyers M.,Ferdinand - Braun - Institute
Applied Physics Letters

A semiconductor disk laser based on an InGaAs/AlGaAs quantum-well gain medium was mode-locked by a fast semiconductor saturable absorber mirror. By high-order harmonic mode-locking a 92 GHz pulse train was obtained with a pulse duration of <200 fs. In order to achieve fundamental mode-locking, too strong saturation of the semiconductor elements had to be avoided. In a single-pulse regime, pulses shorter than 110 fs were generated at a wavelength of 1030 nm. © 2011 American Institute of Physics. Source

Jechow A.,University of Potsdam | Menzel R.,University of Potsdam | Paschke K.,Ferdinand - Braun - Institute | Erbert G.,Ferdinand - Braun - Institute
Laser and Photonics Reviews

A review about second harmonic generation using dge emitting diode lasers and nonlinear crystals to obtain laser adiation in the blue-green spectral range is presented. Therefore, ump laser radiation with high brightness and narrow andwidth is necessary. Thus, this review gives an overview of he advances made with distributed feedback and Bragg reflector asers, tapered lasers and amplifiers as well as external cavity iode lasers and master oscillator power amplifier schemes to achieve high brilliance emission. Since periodically poled materials have enabled high second harmonic conversion efficiencies with low and moderate pump powers, the review is focused on frequency doubling using those materials. The most commonly used materials, their properties and limitations are discussed briefly. Single pass and resonant SHG setups with waveguide and bulk nonlinear crystals are discussed and an emphasis on building compact and integrated devices is made. © 2010 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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