| 摘要 |
PROBLEM TO BE SOLVED: To provide a power meter and an apparatus equipped with the power meter for measuring light intensity, which can adjust optical axes without visually checking the display section of the power meter, when measuring the light intensity. SOLUTION: A photodiode PD, which outputs values of detection current corresponding to the intensity of light received, is disposed in a diffraction grating inspection apparatus 1. When the position of a mount section 41a is varied so that the photodiode PD receives light, an optical axis detecting circuit, in the power meter 50 electrically coupled with the photodiode PD, generates transmission signals having frequencies corresponding to the values of the detected current, and a speaker 53 generates audible sounds having periods corresponding to the transmission signals. The diffraction grating inspection apparatus 1 is adjusted, while listening to the audible sounds, and when the shortest period for the audible sound and high-frequency continuous sounds are found, the intensity of the light received by the photodiode PD becomes a maximum, and the diffraction grating test apparatus 1 is in an optimally adjusted state. COPYRIGHT: (C)2004,JPO&NCIPI
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