Optical attenuator and optical power meter calibration systems with optical-pulse conversion and averaging

An optical power meter calibration apparatus comprising:

• a light source;
• optical path changing means, connected to said light source through a first optical path, for outputting light to a second or third optical path;
• a variable optical attenuator arranged on the first optical path;
• pulse generating means, arranged on either one of the first and second optical paths, for receiving light and outputting first and second optical pulse trains having different values of a period Tf and of a light passing time Tw (Tw.ltoreq.Tf) per period Tf;
• photodetecting means for measuring an average optical power of each of the first and second optical pulse trains which have propagated in the second optical path;
• and
• a wide-range optical attenuator, arranged on the third optical path, for outputting light attenuated by a predetermined attenuation in a wide range to an optical power meter to be calibrated,
• wherein said variable optical attenuator is calibrated by using a ratio between the average optical powers of the first and second optical pulse trains, which are measured by said photodetecting means, as a standard attenuation, and said optical power meter to be calibrated is subsequently calibrated at a optical power level determined by said wide-range optical attenuator.