| 摘要 |
PURPOSE:To measure modulation distortion and a longitudinal mode spectrum at the same time, by splitting the output light from a semiconductor laser module into two beams, and measuring the modulation distortion and the longitudinal mode spectrum based on the split outputs. CONSTITUTION:The output light of a semiconductor laser module 1 is inputted into an optical fiber coupler 3. The output light of the module 1 is split into two beams. A suitable bias is imparted to the semiconductor laser module 1 from a bias circuit 9. Modulation is applied with the electric signal from an analog signal generator 8. One of the two output light beams, which are outputted through the optical coupler fiber coupler 3, is inputted into a photodetector 5. Modulation distortion is measured with a spectrum analyzer 7 through an amplifier 6. Meanwhile, the other output light beam is inputted into an optical spectrum analyzer 4, and a longitudinal mode spectrum is measured. Thus, the modulation distortion and the longitudinal mode spectrum can be measured at the same time.
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