Structure optimization of high speed intracavity-contacted oxide-confined VCSELs
This work presents the simulation of the intracavity contacted oxide confined vertical cavity surface emitting lasers (VCSEL) including the thermal effects. The analysis of thermal, electrical and optical phenomena represents the influence of geometrical parameters on power and modulation properties on such devices.
Current crowding in graded contact layers of intracavity-contacted oxide-confined vertical-cavity surface-emitting lasers
In this work we present the simulation of the intracavity-contacted oxide-confined vertical-cavity surface-emitting lasers including the thermal effects. We analyze the thermal, electrical, and optical properties of such devices with the different thicknesses of graded layers between the contact and oxide confined layers. Results of simulations for the devices with graded layer thickness of 40–60 A show a reduced current crowding effect.
Properties of a monopivot centrifugal blood pump manufactured by 3D printing
An impeller the same geometry as the impeller of a commercial monopivot cardiopulmonary bypass pump was manufactured using 3D printing. The 3D-printed impeller was integrated into the pump casing of the commercially available pump to form a 3D-printed pump model. The surface roughness of the impeller, the hydraulic performance, the axial displacement of the rotating impeller, and the hemolytic properties of the 3D-printed model were measured and compared with those of the commercially available model. Although the surface roughness of the 3D-printed model was significantly larger than that of the commercially available model, the hydraulic performance of the two models almost coincided. The hemolysis level of the 3D-printed model roughly coincided with that of the commercially available model under low-pressure head conditions, but increased greatly under high-pressure head conditions, as a result of the narrow gap between the rotating impeller and the pump casing. The gap became narrow under high-pressure head conditions, because the axial thrust applied to the impeller increased with increasing impeller rotational speed. Moreover, the axial displacement of the rotating impeller was twice that of the commercially available model, confirming that the elastic deformation of the 3D-printed impeller was larger than that of the commercially available impeller. These results suggest that trial models manufactured by 3D printing can reproduce the hydraulic performance of the commercial product. However, both the surface roughness and the deformation of the trial models must be considered to precisely evaluate the hemolytic properties of the model.