Degradation behavior of narrow-spectral-linewidth DFB lasers for super-wide-band FM conversion

The feasibility of using narrow-spectral-linewidth distributed-feedback las ers as subcarrier multiplexing video distribution sources in optical hetero dyne FM converters is shown by investigating degradation modes of the laser s, There is no change in the dynamic properties, such as the FM response an d the composite second-order and composite triple-beat figures, though spec tral linewidth is increased by degradation, The main degradation appears as an increase in spectral linewidth due to 1/f noise caused by buried hetero interface degradation. The FM response, composite second-order, and composi te triple-beat, however, hardly change in the degradation process.