Showing 3 results for Laser Diode
Keshavarz, Kazempour,
Volume 6, Issue 2 (10-2012)
Abstract
The ABCD matrix method is used to simplifying the theoretical coupling efficiency calculation of Elegant Hermite-Cosh-Gaussian (EHChG) laser beams to a Single Mode Fiber (SMF) with a quadric lens formed on the tip. The integrals of coupling efficiency relation are calculated numerically by Boole method. Meanwhile, the structure parameters of surface-lensed fiber are optimized in numerical simulation to achieve maximum coupling efficiency. Results can give some guidance suggestions for designing suitable micro lenses in order to coupling the EHChG laser beams to the SMF.
Zahra Danesh Kaftroudi,
Volume 15, Issue 1 (1-2021)
Abstract
In this work, for the first time, the improved lasing performance of a blue GaN-based laser diode is demonstrated by the introduction and vertical optimization of a new quadruple asymmetric waveguide structure. In the new proposed waveguide structure, in the first step, p-waveguide and electron blocking layers have been omitted. Then a triple asymmetry was considered for the design of an AlGaNp-cladding layer inside the waveguide structure. The performances of the conventional and proposed laser structures were theoretically studied using the photonic integrated circuit simulator in 3D simulation software. The 3deminsional simulations of carrier transport, optical wave- guiding and self-heating were combined self-consistently in the software. A good agreement was achieved between simulations and experiments by careful choice of different material parameters in the physical models. The effects of the AlGaN p-cladding layer properties on the performance of the new quadruple asymmetric waveguide GaN-based laser were theoretically studied. Threshold current, output power, and operation voltage were compared for different composition of Al, doping, and thickness of the AlGaN p-cladding layer. According to the simulation results, the optimized values of Al composition, doping, and thickness of the AlGaN p-cladding layer obtained for high-power performance.
Seyed Peyman Abbasi, Arash Hodaei,
Volume 15, Issue 2 (7-2021)
Abstract
Laser diode beam divergence is the main parameter for beam shaping and fiber optic coupling. Increasing the waveguide layer thickness is the conventional method to decrease the beam divergence. In this paper, the broadened asymmetric waveguide is introduced to decrease the divergence without increasing the optical power. The asymmetric waveguide was used to shift the vertical optical field to n-section, which has lower free carrier loss. The main target in this research is to minimize the internal loss to avoid the disadvantage of the broadened waveguide. Finally the beam divergence was decreased to 35 degrees that is very suitable for the conventional multi-mode optical fiber coupling and the optical power was increased to 2400mW in the laser diode with 100μm stripe width and 1mm cavity length. In addition to the fiber coupling, this improvement can be used for other direct applications that need beam shaping.
