A lens meter capable of easily measuring optical characteristics of far and near viewing sections of a multifocal lens to obtain optical characteristics of a multifocal lens. There is also provided a hybrid RamanEDFA amplifier including a Raman portion and an EDFA portion with a dispersion compensating fiber disposed therebetween. Based on it, before inspecting a wafer to be tested, the invention is capable of self-inspecting each electrical channel and each Pogo pin on the Pogo tower to see if they are respectively in a normal condition, either in an open or short circuit, or if there exists a leakage condition.