| 摘要 |
PURPOSE:To avoid a laser damage by disposing a spectrometer for measuring the wavelength corresponding to the drive current between a laser to be measured and a photodetector, applying the stepwise drive current to the laser, operating the grading of the spectrometer and storing the output of the photodetector so that the output becomes the maximum in a memory, thereby obtaining accurate I-lambda characteristic in a short time. CONSTITUTION:A laser drive current I is flowed from a variable current power source 1 to a laser L, and the output light from the laser is incident through the first lens 2, a chopper CH and the second lens 3 to a spectrometer 5. Then, the output light from the spectrometer 5 is supplied to a photodetector D, and amplified by a lock-in amplifier LA. In this structure, a logic circuit 20 having an A/D converter 7, a CPU 8 containing a memory 9 and a D/A converter 10 is newly inserted to between the amplifier LA and the power source 1, the drive current from the power source 1 is varied stepwisely, the grading of the spectrometer 5 is varied for the respective levels at this time, and the conditions that the output of the photodetector D becomes the maximum is stored in the memory 9. |
