Method and device for testing semiconductor laser

摘要

In testing a distributed feedback semiconductor laser with a grating having a phase shift part, a spectrum of the distributed feedback semiconductor laser is measured. A difference between an intensity of a side mode at a high-frequency-wave side of a main mode and an intensity of a side mode at a low-frequency-wave side of the main mode is calculated. The distributed feedback semiconductor laser is judged non-defective when the difference is more than a certain value.