| 摘要 |
<P>PROBLEM TO BE SOLVED: To recover optical output, in suitable timing, in accordance with the ambient temperature, when the light output is stopped automatically due to thermal runaway. <P>SOLUTION: An optical transmitter 1 comprises an LD 2, an LD drive circuit 5, a monitor PD 4, an APC circuit 6 for controlling a drive current of the LD 2, a temperature monitor 3 and a controller 7. The controller 7 monitors a bias current I<SB>b</SB>contained in the drive current. When the monitor value of the bias current I<SB>b</SB>exceeds the shut-down threshold, the controller controls the APC circuit 6 to stop an optical signal S<SB>out;</SB>and when the value of a monitor signal exceeds a fault discriminating threshold, immediately prior to stopping of the optical signal S<SB>out</SB>, the controller controls the APC circuit 6, to resume generation of the optical signal S<SB>out</SB>in the timing when the monitor value of the ambient temperature becomes lower than the recovery determination threshold. <P>COPYRIGHT: (C)2009,JPO&INPIT |
