Laser Diodes (LDs) are becoming increasingly attractive as small and reliable laser-beam sources,
with applications that include pumping of solid-state lasers, materials processing, and medicine. However,
because of the poor beam quality of its output beam, which affects its direct applications, thus people pay
much attention on how to shape the beam of the high power laser diode bar effectively. In this paper some
typical beam shaping methods, shaping principles, key techniques and shaping effects are discussed. Based on
geometric optical analysis, the collimation properties of the off-axis light wave through a cylindrical lens and
elliptical cylindrical lens are separately analyzed in detail by rays tracing formulas, the collimation effects of
them are also made a comparison.