| 摘要 |
<P>PROBLEM TO BE SOLVED: To control an optical output of an LD (laser diode) module in accordance with abnormality when detecting the abnormality of a monitoring value and to suppress a level variation in output light power of an EDF (Erbium Doped Fiber)optical amplifier which is generated by the cause of interrupting the optical output by detecting the abnormality of the monitoring value. <P>SOLUTION: In this light source 21, a PD (photodiode) 32 and an LD output light monitor 33 monitor the power of output light for monitoring outputted behind an LD 31, and a PD 38 and a modulator output monitor 39 monitors the power of main output light outputted ahead of the LD 31. An optical output alarm detecting part 43 determines that an operating state of the LD 31 is abnormal to immediately attenuate the optical output of the LD 31 when both monitored values of the LD output light monitor 33 and the modulator output monitor 39 are abnormal, determines that a monitor system is abnormal to gradually attenuate the optical output of the LD 31 so as to make an optical output attenuation time constant of the LD 31 equal to or more than a tracking time constant of the EDF optocal amplifier when only one of them is abnormal. <P>COPYRIGHT: (C)2009,JPO&INPIT |
