| 摘要 |
PURPOSE:To improve the efficiency of inspection and selection while eliminating the omission of inspection by introducing one part of an optical output kept constant by a control means to a polarizing means through a lens, extracting a TM mode component and monitoring variation to an operating temperature. CONSTITUTION:An element to be inspected LD is controlled by a control circuit 1 so that an optical output from the element LD is brought to a fixed value P1 and driving currents Id are changed and the element Ld emits light. The element Ld is controlled by feeding back an output from a photodiode PD2 to the control circuit 1. On the other hand, laser beams emitted from the element LD are corrected to a plane wave by a lens 3 because they generate a spherical wave, only a TM mode component is extracted through a polarizing prism 4 and projected to a photodiode PD1, and an output from the photodiode PD1 is amplified by an amplifier 5, and recorded to an XY recorder. When the operating temperature of the element LD is changed continuously by a temperature control circuit 2 at that time, the TM mode component suddenly increases at some operating temperature in an element having a kink. Accordingly, the element, in which the kink is generated, can be selected and removed efficiently within a fixed temperature range. |
