| 摘要 |
PURPOSE:To automatically decide a quality easily and exactly even in case of an element containing a slight defective structure, by deciding whether it is good or not, by the number of crests of a wave crest distribution of an optical current pulse, etc. by a P-N junction semiconductor element. CONSTITUTION:To a P-N junction semiconductor element 1 which has been cooled by liquid nitrogen, etc. in order to prevent influence of a thermal noise, an optical pulse for propagating an optical fiber, etc. is applied in a state that reverse bias voltage has been applied by a regulated power supply 10. An optical current pulse of the element 1, which is outputted in response to said operation is detected through a load resistance 13, etc., and a crest of a wave crest distribution of the optical current pulse is discriminated by a wave crest discriminator 15. Subsequently, a defective element whose number of crests of the wave crest distribution becomes plural by generating a microplasma by a fault of a lattice defect, etc. is decided through a counter for counting the number of crests, a plotter 17, etc., and a quality of the P-N junction semiconductor element containing a slight defective structure can be automatically decided easily and exactly. In this regard, even in case when a dark current pulse is an object, it is all the same as above. |
