Reliability and degradation behavior of highly coherent 1.55 mu m long-cavity multiple quantum well (MQW) DFB lasers

Degradation behavior and reliability of 1.55 mu m highly coherent MQW DFB laser with a long cavity are examined and clarified. The increase in spectral linewidth, due to the increase in 1/f noise and internal optical loss and the instability of the side mode, and the changes in FM response, especially the increase in FM efficiency, occur during degradation, e.g. increase in threshold current. In addition to these basic degradations, the degradation behavior of multisection DFB lasers is also clarified from the viewpoint of device characteristics, such as wavelength and tunability. By clarifying these changes in device characteristics, the possibility of long life for long-cavity MQW DFB lasers in optical coherent transmission systems is shown.<
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