Beam collimation of high-power laser diode array with graded-index fiber lens array

Graded-index (GRIN) fiber lens arrays are fabricated from commercial GRIN fibers to collimate a high-power laser diode array. The beam divergence angles are reduced to 4.2 and 14.7 mrad in the fast and slow axes, respectively. The influences of smile and fluctuation in fiber length are discussed. Using an aspherical focal lens system, about 74% power can be launched into a fiber with a numerical aperture (NA) of 0.22 and a core diameter of 400 mu m. (c) 2008 Society of Photo-Optical Instrumentation Engineers.

Optimum design of 1.4KV trench IGBTs - The next generation of high power switching devices

The Trench Insulated Gate Bipolar Transistor (IGBT) is the most promising structure for the next generation of power semiconductor devices with wide applications ranging from motor control (1-4 kV) to HVDC (6.5 kV). Here we present for the first time an optimum design of a 1.4kV Trench IGBT using a new, fully integrated optimisation system comprising process and device simulators and the RSM optimiser. The use of this new TCAD system has contributed largely to realizing devices with characteristics far superior to the previous DMOS generation of IGBTs. Full experimental results on 1.4kV Trench IGBTs which are in excellent agreement with the TCAD predictions are reported.