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Threshold current and differential quantum efficiency of broad contact lasers with asymmetric facet reflectivity are discussed
with the purpose to reveal factors essential for optimisation of the wall-plug efficiency of such lasers. Lasers with low
front facet reflectivity and short cavity often exhibit behaviour difficult to explain with a classical theory. More rigorous
calculation performed in this work show that differential quantum efficiency is indeed less affected by a change of the front
facet reflectivity or cavity length than predicted by such theory. These findings greatly simplify criteria for optimisation
of the wall-plug efficiency of broad contact lasers with coated facets. 相似文献
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Bohdan Mroziewicz Emil Kowalczyk Lech Dobrzanski Jacek Ratajczak Stainslaw J. Lewandowski 《Optical and Quantum Electronics》2007,39(7):585-595
Performance of external cavity diode lasers with silicon gratings produced by E-beam writing and subsequent reactive ion etching
is described. Optical amplifiers used in the experiments were based on single quantum well heterostructures grown by molecular
beam epitaxy. The lasers were set up in the Littrow configuration and have been designed to allow for wavelength tuning in
the range centred at 960 nm. 相似文献
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Facets of semiconductor optical amplifiers (SOA) designed for external cavity lasers must be coated with an antireflection (AR) film of high quality and extremely low reflectance. Therefore measurements of facet reflectance play a crucial role in the fabrication of such AR coating. The reflectance can be estimated by studying the optical power reflected from the Fabry-Perot cavity formed for that purpose by the examined SOA facet and the end of a single-mode fibre. We have made analysis of practical suitability of such measurement method. Theoretical calculations show that, for the low reflectance coatings, losses due to light coupling into optical fibre cannot be omitted in the analysis of the experimental results. To verify this conclusion a theoretical model was tested for a low reflectance surface and we have found that the relative error of the measurements supported by the theoretical model is on the order of 8%. 相似文献
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Optical properties of an external cavity laser with a semiconductor optical amplifier and two diffraction gratings are described.
The laser has been pigtailed and its emission showed two peaks in the output spectrum. The wavelength of the peaks, and in
particular the spectral spacing between them, could be controlled by adjusting the reflecting elements in the system. The
proposed double-frequency laser may be adopted as a signal source in terahertz generators. 相似文献
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Bohdan Mroziewicz Bo
ena Janowska-Dmoch Tomasz Tkaczyk Marianna Grska 《Optics & Laser Technology》1999,31(4):315
Interference fringes recorded on a rotating substrate through a triangular aperture have been composed to form a polygon consisting of triangular sectors with linear gratings. Such polygons can be considered as a quasi-circular diffraction gratings and serve as a Bragg reflector suitable for application in the CG SE DBR semiconductor lasers. 相似文献
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