| 摘要 |
PURPOSE:To immediately stop the irradiation of a power laser when dirt adheres to the tip of a transmitting fiber and when the fiber is broken on the way by detecting the reflected light level of guide light and 2nd order light due to the burning of the fiber. CONSTITUTION:A laser light 11a radiated from a laser oscillator 11 and a part of guide light 17a are reflected by an incident end face 16a and an outgoing end face 16b and then reached to a half mirror 14. When the transmitting fiber 16 is broken, the 2nd order light to be burning light is reached to the half mirror 14. A filter 18 and a photodetector 19 are arranged on the optical path of the reflected light or the 2nd order light reflected by the half mirror. An output signal from the photodetector 19 is amplified by an amplifier 20 and inputted to one input terminals of comparators 21, 22. Signals from a lower limit reference circuit 23 and an upper limit reference circuit 24 are also inputted to the other input terminals of the comparators 21, 22, the outputs of the comparators 21, 22 are inputted to a sequence control circuit 25 and a laser interrupting device 21 is driven by a shutter driving circuit 26 receiving the output of the circuit 25. |
