LD-PD's beam profiler (beam analyzer, mode profiler) is a diagnostic device for laser beam characterization which can measure the whole optical intensity profile of a laser beam, i.e., not only the beam radius but also the detailed shape.Our Beam profilers are used in various ways to evaluate our DFB,SLD,FP ,VCSEL Laser Diode; a qualitative impression of a beam profile can help during alignment of a laser, whereas measurements of the beam radius at different locations along the beam axis (the caustic) allow one to calculate the M2 factor or the beam parameter product, quantitatively characterizing the beam quality.