Showing papers by "Michael Mikulla published in 1997"
10 Nov 1997
TL;DR: In this paper, the authors discuss the reasons why different epitaxial layers are not equivalent from the beam quality point of view and report measurements made on semiconductor amplifiers of different wafers showing that the choice of the epitaxia structure is crucial to obtain good beam quality.
Abstract: In the last years, very good results have been demonstrated in the field of high power diffraction limited tapered semiconductor lasers and amplifiers. However, to our knowledge, no work was reported on the correlation between the epi-structure and the beam quality. In this paper, we discuss the reasons why different epitaxial layers are not equivalent from the beam quality point of view. We then report measurements made on semiconductor amplifiers of different wafers showing that the choice of the epitaxial structure is crucial to obtain good beam quality.
8 citations
Patent•
25 Apr 1997
TL;DR: In this paper, a diode laser oscillator or amplifier with at least one light conducting semiconductor layer is characterized in terms of the optical filling factor, which describes the light proportion, present inside the optically active zone, of an optical wave guided into the optical waveguide structure.
Abstract: The invention relates to a diode laser oscillator or amplifier having at least one light conducting semiconductor layer. The refractive index of said layer is greater than that of semiconductor layers which surround the light conducting semiconductor layer and form an optical waveguide structure with it. This semiconductor layer has at least one optically active zone inside which stimulated photon emission occurs, and which has an optical filling factor which describes the light proportion, present inside the optically active zone, of an optical wave guided into the optical waveguide structure. The invention is characterized in that the light conducting semiconductor layer is so configured that the optical filling factor is reduced and/or the refractive index of the light-conducting semiconductor layer and the refractive index of the semiconductor layers surrounding the light conducting semiconductor layers are selected in such a way that the optical filling factor is reduced.
6 citations
06 Jun 1997
TL;DR: In this paper, the authors measured and analyzed the room-temperature capacitance-voltage (C-V) characteristics of In0.35Ga0.65As/GaAs MQW laser structures with different doping levels in the active region.
Abstract: We have measured and analyzed the room-temperature capacitance-voltage (C-V) characteristics of In0.35Ga0.65As/GaAs MQW laser structures with different doping levels in the active region. Average doping densities in the well-barrier regions were directly extracted from the as- measured carrier profiles. A model for he C-V measurement, including the self-consistent solution of Poisson and Schroedinger equations, was developed. The carrier profiles obtained from the simulated C-V characteristics do not correspond to the free carrier profiles since the local charge neutrality hypothesis does not hold for QW structures. Thus, the true carrier distribution can only be determined from a full quantum-mechanical simulation of the laser structure. We have determined, form the comparison between experimental and simulated profiles, a conduction band offset (Delta) Ec/(Delta) Eg of 0.81. We have also applied C-V measurements to samples with interdiffused QWs, and obtained the characteristic interdiffusion length.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
2 citations
Patent•
25 Apr 1997
TL;DR: In this article, a diode laser oscillator or amplifier with at least one light conducting semiconductor layer is characterized in terms of the optical filling factor, which describes the light proportion, present inside the optically active zone, of an optical wave guided into the optical waveguide structure.
Abstract: The invention relates to a diode laser oscillator or amplifier having at least one light conducting semiconductor layer. The refractive index of said layer is greater than that of semiconductor layers which surround the light conducting semiconductor layer and form an optical waveguide structure with it. This semiconductor layer has at least one optically active zone inside which stimulated photon emission occurs, and which has an optical filling factor which describes the light proportion, present inside the optically active zone, of an optical wave guided into the optical waveguide structure. The invention is characterized in that the light conducting semiconductor layer is so configured that the optical filling factor is reduced and/or the refractive index of the light-conducting semiconductor layer and the refractive index of the semiconductor layers surrounding the light conducting semiconductor layers are selected in such a way that the optical filling factor is reduced.